[1]
“Estimation of the error of Runge-Kutta’s method in multivariate case”, Ann. Sofia Univ. Fac. Math. and Inf., vol. 83, no. 1, pp. 81–88, Dec. 1992, Accessed: Jan. 11, 2026. [Online]. Available: https://annual.uni-sofia.bg/index.php/fmi/article/view/488