Nitrosoureas in cancer treatment : proceedings of the International Symposium on Nitrosoureas in Cancer Treatment held in Montpellier, France, 26-27 January 1981 / sponsored by the Institut national de la santé et de la recherche médicale, the National Cancer Institute, and the Centre national de la recherche scientifique, under the auspices of the French-American agreement ; editors, B. Serrou, P.S. Schein, J.-L. Imbach