1. Measures of Noncompactness in Metric Fixed Point Theory
2. Banaś, J., Goebel, K. (1980). Measure of Noncompactness in Banach Spaces. Lecture Notes in Pure and Applied Mathematics, Vol. 60. New York: Marcel Dekker.
3. Punti uniti in transformazioni a condominio non compacto;Darbo G.;Rend. Sem. Mat. Univ. Padova,1955
4. A fixed point principle;Sadovskii B. N.;Funktsional. Anal. i Prilozhen,1967