DiblikJ., FečkanM., and PospíšilM. 2013. “Representation of a Solution of the Cauchy Problem for an Oscillating System With Two Delays and Permutable Matrices”. Ukrains’kyi Matematychnyi Zhurnal 65 (1), 58-69. https://umj.imath.kiev.ua/index.php/umj/article/view/2404.