Gilbert, G. T., Larson, L. C., & Krusemeyer, M. (1993). The Wohascum County problem book. Mathematical Association of America.
Cita Chicago (17th ed.)Gilbert, George Thomas, Loren C. Larson, i Mark Krusemeyer. The Wohascum County Problem Book. [Washington, D.C.]: Mathematical Association of America, 1993.
Cita MLA (8th ed.)Gilbert, George Thomas, et al. The Wohascum County Problem Book. Mathematical Association of America, 1993.
Atenció: Aquestes cites poden no estar 100% correctes.