KOSTADINOV, S., K. SCHNEIDER, and M. VENKOVA. “EXISTENCE OF INTEGRAL MANIFOLDS FOR IMPULSIVE DIFFERENTIAL EQUATION WITH SMALL PARAMETER”. Tamkang Journal of Mathematics 29, no. 4 (December 1, 1998): 299–308. Accessed May 5, 2024. https://journals.math.tku.edu.tw/index.php/TKJM/article/view/4259.