B. Błocka, “Free Vibrations of Thin, Elastic, Orthogonally Stiffened Shells of Revolution with Stiffeners Treated as Discrete Elements”, Eng. Trans., vol. 37, no. 1, pp. 65–87, Mar. 1989, Accessed: Jul. 09, 2025. [Online]. Available: https://et.ippt.pan.pl/index.php/et/article/view/1656