The contents of an official record, or of a document authorized to
be recorded or filed and actually recorded or filed, including data
compilations in any form, if otherwise admissible, may be proved by
copy, certified as correct in accordance with Sec. 18.902 or testified
to be correct by a witness who has compared it with the original. If a
copy which complies with the foregoing cannot be obtained by the
exercise of reasonable diligence, then other evidence of the contents
may be given.
