[1] S. BANACH: 
Théorie des opérations linéaires. 1932, Warszawa. 
Zbl 0067.08902[2] N. DUNFORD J. T. SCHWARTZ: 
Linear operators. Part  I, 1958, Interscience Publishers, N. Y., London. 
MR 0117523[4] W. V. PETRYSHYN: 
Remarks on fixed points theorems and their applications. Trans. Amer. Math. Soc. 126, 1967, 43-53. 
MR 0217660[5] M. M. VAJNBERG: Variacionnye metody issledovanija nelinejnych operatorov. 1956, Moskva.