While reading the m4 documentation (www.gnu.org/software/m4/manual, last update on April 02, 2008) I found a small typographical error. In section 1.2 Historical References, there is an allusion to Christopher Strachey. His name was erroneously written as Stratchey. The same mistake can be seen in section 4.2.
This surely ain't the most adequate place for this kind of stuff. Hope it helps anyway.