1. Arkhangel'skiĭ A. V., “Open and close-to-open mappings. Relations among spaces,” Tr. Mosk. Mat. Obs., vol. 15, 181–223 (1966).
2. Arutyunov A. V., “Stability of coincidence points and properties of covering mappings,” Math. Notes, vol. 86, no. 2, 153–158 (2009).
3. Arutyunov A. V. and Zhukovskiy S. E., “Continuous dependence of coincidence points on a parameter,” Set-Valued Var. Anal., vol. 23, no. 1, 23–41 (2015).
4. Mordukhovich B. S., Variational Analysis and Generalized Differentiation. Vol. I. Basic Theory, Springer-Verlag, Berlin (2006) (Grundlehren Math. Wiss.; vol. 330).
5. Berestovskiĭ V. N. and Guijarro L., “A metric characterization of Riemannian submersions,” Ann. Global Anal. Geom., vol. 18, no. 6, 577–588 (2000).