Gilbert, G. T., Larson, L. C., & Krusemeyer, M. (1993). The Wohascum County problem book. Mathematical Association of America.

Gilbert, George Thomas, Loren C. Larson, and Mark Krusemeyer. The Wohascum County Problem Book. [Washington, D.C.]: Mathematical Association of America, 1993.

Gilbert, George Thomas, et al. The Wohascum County Problem Book. Mathematical Association of America, 1993.