On two open problems of contractive mappings. Totik, V. — 1983 Publications de l'Institut Mathématique. Nouvelle Série
Open problems in constructive function theory. Baratchart, L.; Martínez-Finkelshtein, A.; Jimenez, D.; Lubinsky, D.S.; Mhaskar, H.N.; Pritsker, I.; Putinar, M.; Stylianopoulos, N.; Totik, V.; Varju, P.; Xu, Y. — 2006 ETNA. Electronic Transactions on Numerical Analysis [electronic only]