Page, A. L., Miller, R. H., Keeney, D. R., Baker, D. E., Ellis, R. J., Rhoades, J. D., . . . Buxton, D. R. (1982). Methods of soil analysis: Chemical and microbiological properties (2. ed.). Wisconsin: American Society of Agronomy, Soil Science Society of America.

Page, A. L., R. H. Miller, D. R. Keeney, D. E. Baker, Roscoe Jr Ellis, J. D. Rhoades, Richard C. Dinauer, Kristine E. Gates, and Dwayne R. Buxton. Methods of Soil Analysis: Chemical and Microbiological Properties. 2. ed. Wisconsin: American Society of Agronomy, Soil Science Society of America, 1982.

Page, A. L., et al. Methods of Soil Analysis: Chemical and Microbiological Properties. 2. ed. Wisconsin: American Society of Agronomy, Soil Science Society of America, 1982.