1. Parallelism in the development of soil survey and range site concepts;Aandahl;Am. Soc. Agron., Spec. Publ.,1964
2. Agricultural Research Institute. 1966. “A National Program of Research for Agriculture.” Agr. Res. Inst., Washington, D. C. 271
3. Ecology of drought cycles and grazing intensity on grasslands of Central Great Plains;Albertson;Ecol. Monographs,1957
4. Nitrification;Alexander,1965
5. The preservation of endangered habitats and vertebrates of North America;Allen,1966