1. Verlan’ A. F. and Sizikov V. S., Integral Equations. Methods. Algorithms [in Russian], Naukova Dumka, Kiev (1986).
2. Vaĭnberg M. M. and Trenogin V. A., The Branching Theory of Solutions to Nonlinear Equations [in Russian], Nauka, Moscow (1969).
3. Trenogin V. A., Functional Analysis [in Russian], Fizmatlit, Moscow (2007).
4. Trenogin V. A. and Filippov A. F., Nonlinear Analysis and Nonlinear Differential Equations [in Russian], Fizmatlit, Moscow (2003).
5. Loginov B. V. and Sidorov N. A., “Group symmetry of the Lyapunov-Schmidt branching equation and iterative methods in the problem of a bifurcation point,” Math. USSR-Sb., 73, No. 1, 67–77 (1992).