1. Inorganic Plant Poisons and Stimulants 1914
2. McHargue, J. S., Jour. Agr. Research 30: 193 (1925).
3. Sommer, A. L., Plant Physiology 1: 231 (1926).
4. Allison, R. V., Fla. Agri. Exp. Stat. Bul. 190: 33 (1927).
5. Felix, E. L., Phytopathology 17: 49 (1927).