1. Albrecht, W. A. (1930). Dry inoculants for alfalfa. J. Amer. Soc. Agron., 22, 916–918.
2. Albrecht, W. A., and Klemme, A. W. (1939). Limestone mobilizes phosphates into Korean lespedeza. J. Amer. Soc. Agron., 31, 284–286.
3. Aldrich-Blake, R. N. (1932). The fixation of atmospheric nitrogen by bacteria living symbiotically in root nodules of Casuarina equisetifolia. Oxf. For. Mem. No. 14, 1–20.
4. Allison, F. E. (1929). Can nodule bacteria of leguminous plants fix atmospheric nitrogen in the absence of the host? Jour. Agr. Research, 39, 893–924.
5. Atwater, W. O. (1886). On the acquisition of atmospheric nitrogen by plants. Amer. Chem. J., 6, 1–24.