Zgorzelska, Anita, and Hanna Guze. “A Note on Bifurcation of Equilibrium Forms of a Gas Baloon Parachute”. Annales Mathematicae Silesianae, vol. 39, no. 2, May 2025, pp. 368-80, https://journals.us.edu.pl/index.php/AMSIL/article/view/19073.