Marusić M, Allegretti N, Culo F
Experientia. 1978 Oct 15;34(10):1355-6. doi: 10.1007/BF01981468.
Cyclophosphamide given to rats 2 or 5 days after an injection of Yoshida ascites sarcoma cured approximately the same proportion of animals, but the resistance to a subsequent tumor challenge was found only in rats treated with the drug 5 days after tumor injection.