Cita APA (7th ed.)

Soil Survey Staff. (2006). Keys to soil taxonomy (10a. ed.). United States Department of Agriculture. Natural Resources Conservation Service.

Cita Chicago (17th ed.)

Soil Survey Staff. Keys to Soil Taxonomy. 10a. ed. Washington, D.C: United States Department of Agriculture. Natural Resources Conservation Service, 2006.

Cita MLA (9th ed.)

Soil Survey Staff. Keys to Soil Taxonomy. 10a. ed. United States Department of Agriculture. Natural Resources Conservation Service, 2006.