1. Surgeon General's Techn. Rep., Poliomyelitis Surveillance, Rep. No. 268 (September 21, 1962), C. D. C. Atlanta, 1962.
2. Surgeon General's Techn. Rep., Poliomyelitis Surveillance, Rep. No. 269 (October 10, 1962), C. D. C. Atlanta, 1962.
3. Sabin, A. B.: J. A. M. A.183, 268 (1963).
4. Melnick, J. L., andM. Benyesh-Melnick: Live Poliovirus Vaccines, Sc. Publ. of PAHO No. 50, Washington12, (1960).
5. Verlinde, J. D., andJ. B. Wilterdink: ibid.134, 1960.