1.
Bischi G-I, Gardini L, Mira C. New phenomena related to the presence of focal points in two-dimensional maps. Ann. Math. Sil. [Internet]. 1999 Sep. 30 [cited 2025 Dec. 5];13:81-9. Available from: https://journals.us.edu.pl/index.php/AMSIL/article/view/14139