1. Rivers, T. M., “Viral and Rickettsial Infections of Man”, 244 (Philadelphia, 1952).
2. Pond, W. L., Russ, S. B., and Warren, J., J. Infect. Dis., 93, 294 (1953).
3. Pond, W. L., and Russ, S. B., Bull. World Health Org., 12, 591 (1955).
4. McLean, D. M., Aust. J. Exp. Biol. Med. Sci., 34, 71 (1956).
5. Chanock, R. M., and Sabin, A. B., J. Immunol., 73, 337 (1954).