The Mathematical Association of America has a
submit-a-review form that apparently allows readers
to comment on previously reviewed books.
This morning I submitted the following comment on
Alexander Bogomolny's March 16, 2012, review of
Martin J. Erickson's Beautiful Mathematics :
In section 5.17, pages 106-108, "A Group of Operations,"
Erickson does not acknowledge any source. This section
is based on the Cullinane diamond theorem. See that
theorem (published in an AMS abstract in 1979) at
PlanetMath.org and EncyclopediaOfMath.org, and
elsewhere on the Web. Details of the proof given by
Erickson may be found in "Binary Coordinate Systems,"
a 1984 article on the Web at
http://finitegeometry.org/sc/gen/coord.html.
If and when the comment may be published, I do not know.
Update of about 6:45 PM ET June 7:
The above comment is now online at the MAA review site.
Update of about 7 PM ET July 29:
The MAA review site's web address was changed, and the
above comment was omitted from the page at the new address.
This has now been corrected.