Bischi, Gian-Italo, Laura Gardini, and Christian Mira. “Unbounded Not Diverging Trajectories in Maps With a Vanishing Denominator”. Annales Mathematicae Silesianae 13 (September 30, 1999): 91–102. Accessed May 6, 2025. https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/14140.