The following links will take you to the U.S. Government Printing Office website where you can access the Federal Employees Health Benefits Program regulations (www.access.gpo.gov/nara/cfr/cfr-table-search.html).
Once in this website, select Title 5; then select Chapter 1 Parts 700-1199; then select Part 890 for the Federal Employees Health Benefits Program or Part 891 for Retired Federal Employees Hleath Benefits.
PDF documents downloaded from this site will be named "get-crf", and will not have the standard .PDF file ending. You will need to either tell your browser to use Adobe Acrobat to read the file, or save it to your hard disk and rename it, including adding the file extension "PDF", in order to view it.