Jakubec, Stanislav, and Miroslav Laššák. “Congruence of Ankeny-Artin-Chowla Type Modulo p^2”. Annales Mathematicae Silesianae 12 (September 30, 1998): 75–91. Accessed April 11, 2025. https://journals.us.edu.pl/index.php/AMSIL/article/view/14165.