Kocherga, O. I. “Asymptotic Solution of the Cauchy Problem for a Singularly Perturbed Linear System”. Ukrains’kyi Matematychnyi Zhurnal 51, no. 8 (August 25, 1999): 1126–1128. Accessed May 9, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4705.