The structure and metabolism of the pancreatic islets, a centennial of Paul Langerhans' discovery : proceedings of an international symposium held in Umea, Sweden, Feb. 17-19, 1969 - Falkmer, Sture, 1927-; Hellman, Bo, 1930-; Taljedal, I.-B. (Inge-Bert), 1942- (Wenner-Gren Center international symposium series ;, 1970)