Walentyński, Ryszard. “Refined Least Squares Approach to the Initial-Value Problems Unstable in the Lyapunov Sense”. Computer Assisted Methods in Engineering and Science 12, no. 1 (March 31, 2005): 65–81. Accessed February 23, 2026. https://cames.ippt.pan.pl/index.php/cames/article/view/1007.