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

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

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