Smilijanow, Atanas, and Zvetan Mitrov. “ON THE CORRECTNESS OF DIFFERENTIAL AND DIFFERENCE METHODS FOR ANALYSIS OF THE STABILITY OF CONTINUOUS RAILWAYS”. Ann. Sofia Univ. Fac. Math. and Inf. 82, no. 1 (December 12, 1991): 5–12. Accessed December 5, 2024. https://stipendii.uni-sofia.bg/index.php/fmi/article/view/518.