Trąmpczyński, W, and D. Szyba. “Brief Notes: Kinematically Admissible Solutions for the Incipient Stage of Earth Moving Processes in the Cases of Various Pushing Wall Forms”. Engineering Transactions 39, no. 1 (March 31, 1991): 123–134. Accessed June 11, 2025. https://et3.ippt.pan.pl/index.php/et/article/view/1618.