If you want to know a little bit more about the methods supported in
TCM, you can read appendix C.
There is a book written by Roel Wieringa 
that treats a number of methods that are supported by TCM in more
depth. See http://www.cs.vu.nl/~roelw/RE1.ps
for the table of contents.
contains the bibliography of Roel Wieringa. A number of his
reports and articles can be downloaded in PostScript format
via this page or directly from the ftp-site
For finding information about requirements engineering
and software specification methods on the web, the page
http://research.ivv.nasa.gov/~steve/resg/archive/RESources.html is an excellent starting point.