Staněk, Svatoslav. “Leray-Schauder Degree Method in One-Parameter Functional Boundary Value Problem”. Annales Mathematicae Silesianae 10 (September 30, 1996): 111–125. Accessed May 7, 2025. https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/14198.