I have been asked for a source of the NIST document and been
reminded that these documents are old - ie written in 1989
and published by NIST in 1990 - (ahhh. old at 3 years)
all that aside, NIST documents are available (officially) at
National Technical Information Service
U.S. Dept. of Commerce
5285 Port Royal Road
Springfield, VA 22161
and sometimes (unofficially) at
NIST
Technology Bldg. 225 A216
Gaithersburg, MD 20899
Their BBS (which has only a very few documents loaded) is at
301-948-5140 or
CSRC.NIST.GOV
Tom Jones - Lemcom