Girnyk, M. A. 1994. “Approximation of Functions Subharmonic in a Disk by the Logarithm of the Modulus of an Analytic Function”. Ukrains’kyi Matematychnyi Zhurnal 46 (8): 1080–1083. https://umj.imath.kiev.ua/index.php/umj/article/view/5661.