Asymptotics of a generalized matrix renewal function. Sgibnev, M.S. — 2004 Publications de l'Institut Mathématique. Nouvelle Série
An asymptotic expansion of the solution to a system of integrodifferential equations with exact asymptotics for the remainder. Sgibnev, M.S. — 2008 Sibirskij Matematicheskij Zhurnal