Matulka, K. V.     Convergence and stability to perturbations of branched continued fractions with positive elements [Текст] / K. V. Matulka, V. R. Hladun // International conference dedicated to the 120th anniversary of Stefan Banach : abstr. of rep., Lviv, Ukraine, Sept. 17-21, 2012 / I. Franko Nat. Univ. of Lviv, Lviv Politechnic Nat. Univ., Lviv Inst. for Appl. Problem of Mechanics and Mathematics, Donetsk Inst. of Appl. Mathematics and Mechanichs, Kyiv Inst. of Mathematics of Nat. Acad. of Sciences of Ukraine. — 2012. — P. 146.