1. “Introduction to Soil Microbiology,”;Alexander,1977
2. “Principles of Animal Ecology.”;Allee,1949
3. “Soil Organic Matter and Its Role in Crop Production.”;Allison,1973
4. Energy potential from organic wastes: A review of the quantities and sources;Anderson;Inf. Circ. U.S. Bur. Mines,1972
5. “Distribution and Abundance of Animals.”;Andrewartha,1954