1. Billroth, H. Quoted by Hanlon.
2. Hanlon, F. R. Multiple primary carcinomas.Am. J. Cancer (Suppl.)15:2001, 1931.
3. Mercanton, F. Quoted by Hanlon.
4. Warren, S., andGates, O. Multiple primary malignant tumors; survey of literature and statistical study.Am. J. Cancer 16:1358, 1932.
5. Bugher, J. C. Probability of chance occurrence of multiple malignant neoplasms.Am. J. Cancer 21:809, 1934.