W. Trąmpczyński and D. Szyba, “Brief Notes: Kinematically Admissible Solutions for the Incipient Stage of Earth Moving Processes in the Cases of Various Pushing Wall Forms”, Eng. Trans., vol. 39, no. 1, pp. 123–134, Mar. 1991, Accessed: Jan. 17, 2026. [Online]. Available: http://et.ippt.gov.pl/index.php/et/article/view/1618