APA (7th ed.) Citation

United States. Soil Management Support Services & United States. Agency for International Development. (1990). Keys to soil taxonomy (4th ed.). Agency for International Development, U.S. Dept. of Agriculture, Soil Management Support Services.

Chicago Style (17th ed.) Citation

United States. Soil Management Support Services and United States. Agency for International Development. Keys to Soil Taxonomy. 4th ed. [Washington, D.C.]: Agency for International Development, U.S. Dept. of Agriculture, Soil Management Support Services, 1990.

MLA (9th ed.) Citation

United States. Soil Management Support Services and United States. Agency for International Development. Keys to Soil Taxonomy. 4th ed. Agency for International Development, U.S. Dept. of Agriculture, Soil Management Support Services, 1990.