1. Fidler IJ, Kripke ML: Metastasis results from pre-existing variant cells within a malignant tumor. Science (197): 893?895, 1977.
2. Kripke ML, Gruys E, Fidler IJ: Metastatic heterogeneity of cells from an ultraviolet light-induced murine fibrosarcoma of recent origin. Cancer Res (38): 2962?2967, 1978.
3. Dexter DL, Kowalski HM, Blazer BA, Fligiel Z, Vogel R, Heppner GH: Heterogeneity of tumor cells from a single mouse mammary tumor. Cancer Res (38): 3174?3181, 1978.
4. Suzuki N, Withers HR, Koehler MW: Heterogeneity and variability of artificial lung colony-forming ability among clones from a mouse fibrosarcoma. Cancer Res (38): 3349?3351, 1978.
5. Nicolson GL, Brunson KW, Fidler IJ: Specificity of arrest, survival and growth of selected metastatic variant cell lines. Cancer Res (38): 4105?4111, 1978.