Krawczuk, Marek, Wiesław Ostachowicz, and Arkadiusz Żak. “Natural Vibration Frequencies of Delaminated Composite Beams”. Computer Assisted Methods in Engineering and Science 3, no. 3 (September 30, 1996): 233–243. Accessed February 23, 2026. https://cames.ippt.pan.pl/index.php/cames/article/view/1444.