just as a point of information, larry siebenmann says, with regard
to an input encoding of cyrillic that is similar to the one used
for the wncy* fonts:

    The encoding "russian-encoding-tex" is essentially due to
    Barbara Beeton of the AMS.  This version has enough braces
    added to prevent the dangerous ambiguities inherent in
    ligature typing.  But readability and typability suffer.

although technically true that i implemented the input encoding
for the cyrillic in the amsfonts, i was constrained to use the
mathematical reviews transliteration, with two distinct outputs
required:
 - when in "transliteration" mode, the output is the transliterated
   string;
 - when in "cyrillic" mode, the output is the russian/bulgarian/
   ukrainian/serbian/etc. original.

most people either don't know, or have forgotten this, so they are
not aware of the special \cydot command that is required to separate
the two distinct letters "t.s" as opposed to the single letter "ts".
input instructions are given in the amsfonts user's guide --
amsfndoc.tex -- which is available from the ams website in both
source and .ps form (see http://www.ams.org/tex/amsfonts.html).

there is an alternate input encoding for wncy*, with some letters
consisting of a letter plus a digit; this is enumerated in an ascii
file that accompanies the mf source collection.

while these particular fonts and encodings have serious drawbacks,
the principal one being that they are not amenable to automatic
hyphenation, they do precisely fill the requirements of publishing
math reviews, for which they were created.  they were released
publicly to fill a void at the time, very early in the history of
tex.  please do not hold this against them.

if cyrillic fonts are needed for publication in russian or other
slavic languages (or even in non-slavic languages represented in
cyrillic), there are now much better alternatives -- created by
specialists who speak and use those languages daily -- and i
advise that these new fonts and encodings be used instead of the
quite limited wncy*.
-- bb