Microbiology - 1981 Hassan, A. E., & Hassan, H. (1981). Vacuum Drum Planters (Patent No. US4306509A). Hassan, H. M., & Fridovich, I. (1981). Chemistry and biochemistry of superoxide dismutases. European Journal of Rheumatology and Inflammation, 4, 160–172. Hassan, H. M. (1981). Superoxide and superoxide dismutases in Escherichia coli: threat and defense. In K. Bloch, L. Bolis, D. C. Tosteson, & J. Wright (Eds.), Membranes, Molecules, Toxins, and Cells (pp. 123–133). Boston: PSG Inc. Miller, E. S., & Brenchley, J. E. (1981). L-Methionine SR-sulfoximine resistant glutamine synthetase from mutants of Salmonella typhimurium. Journal of Biological Chemistry, 256(21), 11307–11312. https://doi.org/10.1016/S0021-9258(19)68592-3 Hollis, A. B., Kloos, W. E., & Elkan, G. H. (1981). DNA:DNA hybridization studies of Rhizobium japonicum and related Rhizobiaceae. Journal of General Microbiology, 123(2), 215. STOWERS, M. D., & ELKAN, G. H. (1981). AN INDUCIBLE IRON-CONTAINING SUPEROXIDE-DISMUTASE IN RHIZOBIUM-JAPONICUM. CANADIAN JOURNAL OF MICROBIOLOGY, 27(11), 1202–1208. https://doi.org/10.1139/m81-185