AndrusyakI. V., and FilevychP. V. “The Coefficients of Power Expansion and $a$-Points of an Entire Function With Borel Exceptional Value”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 68, no. 2, Feb. 2016, pp. 147-55, http://umj.imath.kiev.ua/index.php/umj/article/view/1829.