1. Herdman, W. A., and Boyce, R., (1899): cited from The Japanese Journal of Hygiene and Infectious Diseases 24, 418, 1918.
2. Smith, Th. (1904): Ditto
3. Cumming, H. S., U. S. Hygienic Lab. Bull. 104, 1915.
4. Toyama, Y., Japanese Journal of Infectious Diseases 4, 101, 1928.
5. Yamaguchi, S., Kokumin Eisei, The National Hygiene 3, 4, 609, 1926.