July 22, 1998
1. THE EOSS DOCUMENT CLASS AND ITS 19 DOCUMENT SUBCLASSES
The EOSS (Engineering Operational Sequencing System) document class consists of 19 document subclasses. There are 9 document subclasses
- Component Procedure (CP)
- Master Plant Procedure (MPP)
- Operational Procedure (OP)
- System Procedure (SP)
- System Control Procedure (SCP)
- Fuel Control Procedure (FCP)
- Valve Table (VT)
- Standard Notes (SN)
- Standard Warning (SW)
whose formatted documents have a size of 8 1/2" by 11" with "portrait" orientation. There are 4 corresponding document subclasses
- Master Plant Procedure Landscape (MPL)
- Operational Procedure Landscape (OPL)
- System Procedure Landscape (SPL)
- Valve Table Landscape (VTL)
whose formatted documents have a size of 8 1/2" by 11" with "landscape" orientation. Finally, there are 5 document subclasses
- Casualty Response Procedure (CRP)
- Master Casualty Response Procedure (MCR)
- Emergency Procedure (EP)
- Master Emergency Procedure (ME)
- Master Emergency Plant Procedure (MEP)
whose formatted documents have a size of 5 1/2" by 8 1/2" with "portrait" orientation.
The 19th document class is the Diagram (DIA). Diagrams consist of one or more graphics along with some identification material. They are unique in that they constitute a document subclass in their right and are also integral parts of documents of other subclasses.
It was the intent of NSWCCD-SSES that a single DTD be developed to accommodate these 19 EOSS document subclasses.
1.1 TRADITIONAL CALS MODELLING APPROACH
Traditionally, CALS DTDs have modelled document classes in terms of:
- "front matter" (identification information and preliminary material such as TOCs, introductions, etc.),
- "body matter" (the substance of the document with regard to content matter as opposed to bulk)
- "rear matter" (appendixes, concluding matter, etc.)
However, this approach did not seem particularly relevant with regard to the EOSS documents. The following approach was taken instead.
1.2 EOSS MODELLING APPROACH
The identification information - publication number (consisting of the master code, sequential number, and publication date) and the prime (document) title - is common to all 19 document subclasses. The prime title and the master code are provided in the first row of the first page and the publication number and page number are provided in the last row of every page of the EOSS document.
The first row consists of two boxes. The first box has the document subclass for a heading over the document's title. The second box contains the mastercode under a heading composed of the acronym for the document subclass followed by "NO.", e.g., "C.P. NO.", "SCP. NO.", etc. with the following exceptions. The landscape oriented documents use the acronym for their portrait oriented counterparts. The 5 1/2" by 8 1/2" size documents contain "I.D." instead of the document subclass acronym, e.g., "I.D. NO.".
From this point on, the additional required contents for the different document subclasses differ significantly. However, they consist of components (such as User Notes areas, Done Procedures Checklist areas, sequential lists, etc.) some of which occur in several document subclasses and which are easily modelled as element types. It seemed reasonable to model the additional required contents for each document subclass in terms of subelement types which were the models of these common document components. This approach provided much more of a capability to enforce the conformity of EOSS documents to their required contents than that of the traditional front matter and body matter modelling.
The identification information is provided as the content of the "pubno" and "prtitle" element types which are common to all 19 document subclasses.
1.3 MODELLING THE REQUIRED CONTENTS OF THE 19 DOCUMENT SUBCLASSES
Both Operational Procedure, System Notes, Casualty Response Procedure, and Emergency Procedure subclass documents contain a page-wide box containing text headed "WATCH AREA" in a second row. Component Procedure documents contain a similar box headed "C.P. Description" containing an un-enumerated list of the titles in the following Procedural Area. These second-row boxes are followed by the additional required contents for their document subclass as described below.
The additional required contents of the Component Procedure and both of the System Procedure subclass documents consists of a text area headed PROCEDURE. The System Procedure subclass documents may also have an optional text area headed USER NOTES.
The additional required contents of both Master Plant Procedure and both Operational Procedure, subclass documents consists of a text area headed "NOTES:" followed by a two column display whose left column is headed "USER NOTES" and whose right column is headed by the documents title (but only after the first page). NOTE: The EOSS DTD allows a choice of a "USER NOTES" or "DONE PROCEDURES" area (see below) to accommodate the future reclassification of present FCP and SCP documents as MPPs.
The additional required contents of the Standard Notes subclass documents consists of unheaded text in the form of sequential lists.
The additional required contents of the Standard Warning subclass documents consists of a text area headed "WARNING".
The additional required contents of the Master Casualty Response Procedure, Master Emergency Procedure, and Master Emergency Plant Procedure subclass documents consists of unheaded text in the form of sequential lists followed by a two-column display whose left column is headed "USER NOTES" and whose right column is headed by the document's title (but only after the first page).
The additional required contents of the Casualty Response Procedure and Emergency Procedure subclass documents consists of a two-column display whose left column is headed "USER NOTES" and whose right column is headed by the documents title (but only after the first page).
The additional required contents of the System Control Procedure subclass documents consists of a text area headed "NOTES:" and followed by a two-column display whose left column is headed by "DONE" and whose right column is headed by "PROCEDURE".
The additional required contents of the Fuel Control Procedure subclass documents consists of a text area headed "NOTES:" and followed by a two-column display whose left column is headed by "DONE" and whose right column is headed by "PROCEDURE". However, in some cases this display may be replaced by a two-column display whose left column is headed "USER NOTES" and whose right column is headed by the documents title (but only after the first page).
2. ELEMENT TYPE DEFINITIONS
The element types of the EOSS DTD are defined below in alphabetical order.
The term "text" occurs in some of the element type definitions. It means any of the options of the replacement text of "%text;", i.e., any combination of parsed character data and the markup of the following element types: "subscrpt", "supscrpt", "negtext", "emphasis", "dia", "dialink", "change", "xref", and "extref" defined below.
The term "list" also occurs in some of the element type definitions. It means one or more sequential lists, random lists, or definition lists or combination thereof.
All EOSS DTD element types have required start- and end-tags with the exception of those element types with EMPTY declared content and some of the CALS table model element types.
Some of the EOSS DTD element types have an ID attribute "id" to enable cross-referencing within the document as opposed to cross-referencing outside of the document by using the "xlink" attribute.
Some of the element types have a CDATA attribute "label" for identification or enumeration purposes.
2.1 CAUTION: Caution
This tag identifies a caution. Its content consists of paratexts and/or lists. Its information is preceded by "CAUTION:". Cautions can occur throughout an EOSS document.
This element type has the customary ID attribute "id" and the CDATA attribute "label".It also has the CDATA attribute "xlink" to enable external linkages.
2.2 CAUTIONS: Set of Cautions
This tag identifies a set of cautions. Its content is a sequential list (enumerated with arabic numerals) whose items contain the information of the cautions. The information of the first caution is preceded by "CAUTIONS:". Sets of cautions can occur throughout an EOSS document.
This element type has the customary ID attribute "id" and the CDATA attribute "label".It also has the CDATA attribute "xlink" to enable external linkages.
2.3 CHANGE: Change Information (Used to Provide Change Bars) -->
This tag identifies change information that is used to provide change bars in the margin. Its content consists of the "%text;" options. The optional "id" attribute value identifies the change for cross-referencing. The optional "change" attribute value identifies the change as an addition ("add") or a deletion ("delete"). The optional CDATA "level" attribute value identifies the change level for configuration control.
2.4 CHART: Chart
The CALS table model element "chart" is not used at present in the EOSS application.
2.5 COLSPEC: Column Specification
This element specifies the width of a column of a table. It is an EMPTY element type: it can have no content and the "colspec" start-tag must not be followed by a "colspec" end-tag.
Always specify the "colname" attribute as "1", "2", "3", etc. on each "colspec" tag for each consecutive column. (Do not confuse the "colname" attribute with the "colnum" attribute which you do not specify on the "colspec" tag.)
Specify the value of the "colwidth" attribute as the column width in terms of the maximum number of characters the column can hold. For a "port" table, the sum of the values of the "colwidth" attributes should not exceed 70; likewise the sum of the "colspec" values should not exceed 110 for a "land" table.
Do not specify the "colnum", "charoff", "char", or "rowsep" attributes on the "colspec" tag.
2.6 CP: Component Procedure
This element type is used to contain the required contents of the component description subclass document. In addition to the prime title and the publication number, they consist of a component procedure description area followed by a procedure area.
2.7 CPDES: Component Procedure Description
This tag identifies a component procedure description area following the heading of an Component Procedure subclass document. It consists of one or more component procedure names (tagged in terms of "topic") following a "C. P. DESCRIPTION" heading.
2.8 CRP: Casualty Response Procedure
This element type is used to contain the required contents of the casualty response procedure subclass document. In addition to the prime title and the publication number, they consist of a watch area box followed by a user notes area.
2.9 DEF: Definition
This element type identifies a definition of a term-definition pair in a definition list. Its content consists of paratexts and/or sequential lists.
2.10 DEFLIST: Definition List
This element type identifies information provided in the term-definition pair format.
The "deflist" element has one attribute "type" whose values are "regular" and "valve" with a default value of "valve". The "type" attribute indicates whether or not the "deflist" element is used to present valve information.
2.11 DIA: Diagram
This element type identifies a diagram consisting of identification material and one or more graphics. The same diagram may occur several times in one document or in several documents. Diagrams are also considered a document subclass in their own right.
The value of the required "label" attribute on the "dia" tag is assigned as follows:
(1) If the diagram is considered a document in its own right (the "doceoss" start-tag precedes the "dia" start-tag and the "doceoss" end-tag follows the "dia" end-tag in the instance), then the value of the "label" attribute is the entire diagram publication number, e.g., label="DACW/0068/011593".
(2) If the "dia" content is part of another document's content in the instance (the "dia" start-tag is preceded by "see diagram" or similar wording), then the value of the "label" attribute is merely the mastercode portion of the diagram publication number, e.g., label="DACW".
2.12 DIALINK: Diagram Link
This element type identifies a link from from a valve number reference in text to the valve number in a graphic. It has CDATA content.
The value specified for the optional CDATA attribute "ident" uniquely identifies the valve number reference. The value of the required "boardno" attribute is the name of an external NDATA ("tiff") or CGM external entity declared in the declaration subset of the Document Type Declaration (DOCTYPE) heading the instance. The value for the required CDATA "hypdestn" attribute specifies the valve number.
2.13 DOCEOSS: Document Level Element for EOSS Documents
This is the tag of the document level (root or highest order) element type for EOSS documents.
2.14 DONEPROC: Done Procedures Checklist
This tag identifies a done procedures checklist. A done procedures checklist consists of a two-column display whose right column contains one or more lists headed by "PROCEDURE".
2.15 EMPHASIS: Emphasis
This tag identifies author-specified emphasis (underlining or bolding) for the text contained between the "emphasis" start- and end-tags.
The type of emphasis is specified by setting the "type" attribute on the "emphasis" tag to "underline" or "bold" or "valve" (to denote valve information).
2.16 ENTRY: Entry
This tag identifies an entry in a table heading or table row. Its content consists of parsed character data and other "%text;" options and/or lists.
Always specify the "colname" attribute on the "entry" tag as "1", "2", etc. in agreement with the entry's column "colspec" tag. Specify the "namest" and "nameend" attributes in the same way if the entry spans columns.
The value of the "spanname" attribute is the name of a column span previously defined on a "spanspec" tag. Use either the "spanname" attribute or "namest" and "nameend".
Do not specify the "morerows", "colsep", "rowsep", "rotate", "valign", "charoff", "char", or "idref" attributes on the "entry" tag.
2.17 ENTRYTBL: Entry Table
The CALS table model element type "entrytbl" is not used at present in the EOSS application.
2.18 EP: Emergency Procedure
This element type is used to contain the required contents of the emergency procedure subclass document. In addition to the prime title and the publication number, they consist of a watch area box followed by a user notes area.
2.19 EXTREF: External Document Reference
This tag identifies a reference to an external document. It has EMPTY declared content, i.e., no content or end-tag.
The value of the CDATA "docno" attribute is the document number (or other identification) of the external document referred to.
Do not specify either the "pretext" or "posttext" attributes.
2.20 FCP: Fuel Control Procedure
This element type is used to contain the required contents of the fuel control procedure subclass document. In addition to the prime title and the publication number, they consist of a note area followed by a done procedures checklist area or in some cases by a user notes area but not both. NOTE: At some point in the future, fuel control procedure documents will be re-classified as master plant procedure documents.
2.21 GRAPHIC: Graphic
This tag identifies an externally-stored graphic.
The value of the required "boardno" attribute is the name of an external NDATA ("tiff") or CGM external entity declared in the declaration subset of the Document Type Declaration (DOCTYPE) heading the instance. Its ENTITY declaration identifies the appropriate graphic file.
The value of the required "label" attribute on the "graphic" tag is assigned as follows. A diagram consists of one or more graphics. The value of the "label" attribute on the first "graphic" tag is always "PAGE 1". If the diagram consists of more than one graphic, the "label" attribute on the second "graphic" tag has the value "PAGE 2" and so on.
The optional "graphic" ID attribute "id" enables cross-referencing within the document.
2.22 ITEM: Item
This tag identifies an item of a sequential or random list. Its content consists of paratexts and/or lists.
This element has the customary ID attribute "id" and the CDATA attribute "label".
2.23 MASTERCODE: Master Code
This tag identifies the master code (first) component of a publication number. It consists of several upper-case letters. In the publication number "MABL/0360/030395", "MABL" is the master code.
2.24 MCR: Master Casualty Response Procedure
This element type is used to contain the required contents of the master casualty response procedure subclass document. In addition to the prime title and the publication number, they consist of at least one list followed by a user notes area.
2.25 ME: Master Emergency Procedure
This element type is used to contain the required contents of the master emergency procedure subclass document. In addition to the prime title and the publication number, they consist of at least one list followed by a user notes area.
2.26 MEP: Master Emergency Plant Procedure
This element type is used to contain the required contents of the master emergency plant procedure subclass document. They consist of optional lists followed by a user notes area.
2.27 MPL: Master Plant Procedure Landscape
This element type is used to contain the required contents of the master plant procedure landscape subclass document. In addition to the prime title and the publication number, they consist of a note area followed by a user notes area. NOTE: The EOSS DTD allows the option of a user notes area or a done procedures area to accommodate the future reclassification of the fuel control procedure and system control procedure documents as master plant procedure documents.
2.28 MPP: Master Plant Procedure
This element type is used to contain the required contents of the master plant procedure subclass document. In addition to the prime title and publication number, they consist of a note area followed by a user notes area. NOTE: The EOSS DTD allows the option of a user notes area or a done procedures area to accommodate the future reclassification of the fuel control procedure and system control procedure documents as master plant procedure documents.
2.29 NEGTEXT: Negative Text
This tag identifies the author-specified emphasis of negative words ("no", "not", etc.) in text.
2.30 NOTE: Note
This tag identifies a note. Its content consists of paratexts and/or lists. Its information is preceded by "NOTE:". Notes can occur throughout an EOSS document.
This element type has the customary ID attribute "id" and the CDATA attribute "label". It also has the CDATA attribute "xlink" to enable external linkages.
2.31 NOTEAREA: Note Area
This tag identifies a note area. A note area can consist of any combination of primary paragraphs, lists, and notes following a "NOTES:" heading.
2.32 NOTES: Set of Notes
This tag identifies a set of notes. Its content is a sequential list (enumerated with arabic numerals) whose items are the information of the notes. The information of the first note is preceded by "NOTES:".Sets of notes can occur throughout an EOSS document.
This element type has the customary ID attribute "id" and the CDATA attribute "label". It also has the CDATA attribute "xlink" to enable external linkages.
2.33 OP: Operational Procedure
This element type is used to contain the required contents of the operational procedure subclass document. In addition to the prime title and the publication number, they consist of a watch area box followed by a note area followed by a user notes area.
2.34 OPL: Operational Procedure Landscape
This element type is used to contain the required contents of the operational procedure landscape subclass document. In addition to the prime title and the publication number, they consist of a watch area box followed by a note area followed by a user notes area.
2.35 PARA: Paragraph
This tag identifies an untitled paragraph. Its content consists of paratexts and/or lists. Optional or repeated paragraphs follow the optional title of a primary paragraph.
This element type has the customary ID attribute "id" and the CDATA attribute "label". It also has the CDATA attribute "xlink" to enable linkage across documents.
2.36 PARA0: Primary Paragraph
This tag identifies a primary paragraph. Its content consists of an optional title followed by one or more paragraphs. Primary paragraphs can occur in procedure areas, warning areas, or note areas.
This element type has the customary ID attribute "id" and the CDATA attribute "label".
2.37 PARATEXT: Paragraph Text
This tag identifies a block of text consisting of parsed character data and the other "%text;" options.
2.38 PROCAREA: Procedure Area
This tag identifies a procedure area. A procedure area consists of primary paragraphs and/or lists following a "PROCEDURE" heading.
2.39 PRTITLE: Prime Title
This tag identifies the prime title (document title) of an EOSS document. The prime title consists of alphanumeric characters, subscripts, and superscripts. It is the first required element of the EOSS document heading.
2.40 PUBDATE: Publication Date
This tag identifies the publication date (third) component of the publication number of an EOSS document. It consists of six digits in the format MMDDYY. In the publication number "MABL/0360/030395", "030395" (March 3, 1995) is the publication date.
2.41 PUBNO: Publication Number
This tag identifies the publication number of an EOSS document. It consists of three components: the master code, the sequential number, and the publication date separated by forward slashes (/). An example of a publication number is "MABL/0360/030395". The publication number is the first and required element of the EOSS document heading.
2.42 RANDLIST: Random List
This tag identifies a random list, i.e., an un-enumerated list. The value of the optional CDATA attribute "prefix" precedes all items in the random list.
2.43 ROW: Table Row
This tag identifies a row of a table heading or a table body. A table row consists of one or more entries since entry tables are not used in the EOSS application.
Do not specify the "rowsep" attribute on the "row" tag.
2.44 SCP: System Control Procedure
This element is used to contain the required contents of the system control procedure subclass document. In addition to the prime title and the publication number, they consist of a note area followed by a done procedures checklist. NOTE: At some point in the future, system control procedure documents will be re-classified as master plant procedure documents.
2.45 SEQLIST: Sequential List
This tag identifies a sequential list. A sequential list can have an optional title and must contain at least one item. Sequential lists are commonly-occurring components of EOSS documents. Sequential lists can occur in procedure areas, warning areas, note areas, user notes areas, done procedures checklists, paragraph texts, warnings, cautions, notes, and list items.
This element type has the customary ID attribute "id" and the CDATA attribute "label".
The "numstyle" attribute specifies the enumeration style of the list items as: arabic, arabic in parentheses, upper-case alphabetic, lower-case alphabetic, lower-case alphabetic in parentheses, upper-case roman, lower-case roman, and none.
The content of the typical EOSS document consists mainly of enumerated items, i.e., sequential lists. The usual enumeration schemes for these lists and their sublists are either "I.-A.-1.-a.-(1)-(a)" or "1.-a.-(1)-(a)". For the first enumeration scheme, the items with upper-case roman numerals are considered to be the titles of sublists and the upper-case roman numerals are specified as values of the "label" attribute on the "title" tags, and the upper-case alphabetic enumeration is specified on the "seqlist" start-tag, e.g.,
<title label="I.">
<seqlist numstyle="alphauc">
Specifying the "numstyle" attribute on the "seqlist" tag as follows provides various enumerations for the list items:
NUMSTYLE ENUMERATION arabic 1., 2., ... arabic-parens (1), (2), ... romanuc I., II., ... romanlc i., ii., ... alphauc A., B., ... alphalc a., b., ... alphalc-parens (a), (b), ...
The value of "none" for the "numstyle" attribute is used when the items of the list are not to be enumerated.
2.46 SEQNO: Sequential Number
This tag identifies the sequential number (second) component of the publication number of an EOSS document. It consists of four digits. In the publication number "MABL/0360/030395", "0360" is the sequential number.
2.47 SN: Standard Notes
This element type is used to contain the required contents of the standard notes subclass document. In addition to the prime title and the publication number, they consist of a watch area box followed by at least one sequential list.
2.48 SP: System Procedure
This element type is used to contain the required contents of the system procedure subclass document. In addition to the prime title and the publication number, they consist of a procedure area and an optional user notes area.
2.49 SPANSPEC: Spanned Column Specification
This tag identifies a column span.
On the "spanspec" tag, specify the values of the "namest" and "nameend" attributes as the values of the "colname" attributes of the leftmost and rightmost columns of the span.
Specify the value of the "spanname" attribute as these two values joined with a dash ("-"), e.g., "1-4".
Specify the "align" attribute value as "center", "right", or "left" as the situation warrants.
Do not specify the "charoff", "char", "colsep" or "rowsep" attributes on the "spanspec" tag.
2.50 SPL: System Procedure Landscape
This element type is used to contain the required contents of the system procedure landscape subclass document. In addition to the prime title and the publication number, they consist of a note area followed by an optional user notes area.
2.51 SUBSCRPT: Subscript
This tag identifies a subscript. It consists of one or more alphanumeric characters. Subscripts occur in text.
2.52 SUPSCRPT: Superscript
This tag identifies a superscript. It consists of one or more alphanumeric characters. Superscripts occur in text.
2.53 SW: Standard Warning
This element type is used to contain the required contents of the standard warning subclass document. In addition to the prime title and the publication number, they consist of a warning area.
2.54 TABLE: Table
This tag identifies a table. A table can stand alone or be embedded in text.
On the "table" tag, specify the following attribute values: frame = "0", colsep= "1", orient = "port" ("land" for a VTL or SPL document), and pagewide = "1".
2.55 TBODY: Table Body
This element type contains the rows comprising the table body.
Do not specify the "valign" attribute on the "tbody" tag.
2.56 TERM: Term
This tag identifies the term of a term-definition pair in a definition list.
2.57 TFOOT: Table Foot
The CALS table model element type "tfoot" is not used at present in the EOSS application.
2.58 TGROUP: Table Group
This element type contains the information that defines a table: the table headings, column specifications, and table body.
On the "tgroup" tag, specify the "cols" attribute value as the number of columns.
Use the "align" attribute to specify the alignment of the columns as "left", "center" or "right" (do not use the "justify" or "char" values). If not all the columns are aligned the same way, redefine the alignment for the exceptions by specifying the "align" attribute on their "colspec" tag.
Do not specify the "rowsep", "charoff", or "char" attributes on the "tgroup" tag.
2.59 THEAD: Table Head
This tag identifies a row of the heading in a table.
Do not specify the "valign" attribute on the "thead" tag.
2.60 TITLE: Title
This tag identifies the optional title of a primary paragraph, paragraph text, or a sequential list. It has "%text;" content.
The optional "title" ID attribute "id" enables cross-referencing within the document.
The optional "title" CDATA attribute "label" is used for identification rather than the cross-referencing enabled by the ID attribute "id".
2.61 TOPIC: Topic
This tag identifies a topic in the component procedure description box on a Component Procedure document. It will be the title of a sequential list in the procedure area.
The values of the required "idref" attribute on the "topic" tags in the "cpdes" content (Component Procedure Description box) will be the values of the "id" attribute on the corresponding "title" tags in the Procedure Area corresponding to these "topic" contents.
2.62 USERNOTES: User Notes Area
This tag identifies a user notes area. A user notes area consists of of a two-column display containing one or more sequential lists in the right column headed with document's title on the second and following pages of the document.
2.63 VERBATIM: Verbatim Text
The use of this tag is strongly discouraged.
2.64 VT: Valve Table
This element type is used to contain the required contents of the valve table subclass document. In addition to the prime title and the publication number, it consists of one or more tables.
2.65 VTL: Valve Table Landscape
This element type is used to contain the required contents of the valve table landscape subclass document. In addition to the prime title and the publication number, it consists of one or more tables.
2.66 WARNAREA: Warning Area
This tag identifies the warning area of a Standard Warning subclass document. It consists of primary paragraphs and/or sequential lists following a "WARNING" heading.
2.67 WARNING: Warning
This tag identifies a warning. Its content consists of paratexts and/or sequential lists. Its information is preceded by "WARNING:".
This element has the customary ID attribute "id" and the CDATA attribute "label".It also has the CDATA attribute "xlink" to enable external linkages.
2.68 WARNINGS: Set of Warnings
This tag identifies a set of warnings. The text of the first warning is preceded by "WARNINGS:". The warning texts are enumerated with arabic numerals. A set of warnings can occur throughout an EOSS document. It is modelled by a sequential list whose items are the warning texts.
This element type has the customary ID attribute "id" and the CDATA attribute "label".It also has the CDATA attribute "xlink" to enable external linkages.
2.69 WATCHAREA: Watch Area Text
This tag identifies the text of the watch area box following the heading of portrait and landscape Operational Procedure, System Note, Casualty Response Procedure, and Emergency Procedure subclass documents.
2.70 XREF: Internal Cross-Reference
This tag identifies an internal cross-reference. The value of the required IDREF attribute "xrefid" is the value of the corresponding ID attribute on the tag referred to. The value of the required "xidtype" atribute specifies the material referred to as being a figure ("figure"), a table ("table"), or a reference in text ("text"). The optional CDATA "pretext" attribute is not used in EOSS work. NOTE: This element type has EMPTY declared content.