1. Berger M, Habs M, Schmähl D (1983) Noncarcinogenic chemotherapy with combination of vincristine, methotrexate and 5-fluorouracil (VMF) in rats. Int J Cancer 32:231?236
2. Dexter DL, Calabresi P (1982) Intraneoplastic diversity. Biochim Biophys Acta 695:97?112
3. Drewinko B, Yang LY (1988) The heterogenous cytotoxic response of colon cancer cells is unrelated to phenotypic differentiation characteristic. Anticancer Res 8:161?164
4. Heppner G (1984) Tumor heterogeneity. Cancer Res 44:2259?2265
5. Pu PY, Shapiro WR, Shapiro JR (1983) Correlation of chromosome number to BCNU sensitivity in freshly resected human gliomas tested by colony-forming assays in monolayer culture (meeting abstract) Proc Am Assoc Cancer Res 24:1122