1. Alman, M.: A fixed point theorem in Banach space. Bull. Acad. Polon. Sci. C. III5, 89?92 (1957).
2. Borisovic, Ju. G., Sapronov, Ju. I.: A contribution to the topological theory of condensing operators. Soviet Math. Doklady9, 1304?1307 (1968).
3. Browder, F. E.: A new generalization of the Schauder fixed point theorem. Math. Ann.174, 285?290 (1967).
4. ?: The fixed point theory of multi-valued mappings in topological vector spaces. Math. Ann.177, 283?301 (1968).
5. Danes, J.: Some fixed point theorems. Comment. Math. Univ. Carolinae9, 223?235 (1968).