Staněk, Svatoslav. “Leray-Schauder Degree Method in One-Parameter Functional Boundary Value Problem”. Annales Mathematicae Silesianae 10 (September 30, 1996): 111-125. Accessed May 19, 2024. https://www.journals.us.edu.pl/index.php/AMSIL/article/view/14198.