1. R. S. Bred, E. G. D. Murray and N. R. Smith, “Bergey’s Manual of Determinative Bacteriology,” 7th Ed., Williams and Wilkins Co., 1957.
2. FL Sund, “Biological Oxidation,” Interscience Publishers, A: Division of John Wiley & Sons, New York, London, Sydney, 1968, p. 675.