Aside from the correction that Friedman should be Friedberg, there are the following items:
Dale Seymour Publ. (0) 1-800-872-1100
I have just added two more items under the heading of Encylopedia.
Seymour, D., Encyclopedia of mathematical topics and references, Dale Seymour Publ., 1994.
This is designed for students in search of a projects.
Encyclopedic Dictionary of Mathematics, MIT Press, 1987. 2nd (paperback now available in 2 volumes),
This is an excellent collection of articles written by Japanese mathematicians. It essentially covers the main areas of what might be called "mainstream mathematics" where Japanese mathematicians have made contributions. If you look for fractals, you won't find it. However, in that general area, Shishikura has made important contributions at the cutting edge. Most of the topics are too advanced for 12-th graders. However, it does provide a place where one can point to the links to most of the frontiers.