Howykowycz, Mariya     Development of "surface" shape elements on the basis of invariant approximations technique [Текст] / Mariya Howykowycz // Computational problems of electrical engineering / Lviv Polytechnic nat. univ. ; ed.-in-chief Yuriy Bobalo. — Lviv : lviv Polytechnic nat. univ., 2012. — P. 37-40.