Dudkin, M. Y., and V. I. Kozak. “Jacobi-Type Block Matrices Corresponding to the Two-Dimensional Moment Problem: Polynomials of the Second Kind and Weyl Function”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 68, no. 4, Apr. 2016, pp. 495-0, https://umj.imath.kiev.ua/index.php/umj/article/view/1855.