Plachtyna, Omeljan     Mathematical model of a synchronous machine based on the method of average voltages on an integration step [Текст] / Omeljan Plachtyna, Andriy Kutsyk // Computational problems of electrical engineering / Lviv Polytechnic nat. univ. ; ed.-in-chief Yuriy Bobalo. — Lviv : lviv Polytechnic nat. univ., 2012. — P. 95–100.