Simonovski, P., N. Avramov, S. Simeonov, S. Milev, and Z. Sovreski. “Impact of the Structural Forms of Diaphragm Spring Beginning on Dynamic Durability of Diaphragm Springs of Vehicle Clutches”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 36, no. 3, Oct. 2017, pp. 291-00, https://www.gssrr.org/index.php/JournalOfBasicAndApplied/article/view/8169.