An, Vu Hoai, and Ha Huy Khoai. “Value-Sharing Problem for P-Adic Meromorphic Functions and Their Difference Operators and Difference Polynomials”. Ukrains’kyi Matematychnyi Zhurnal, vol. 64, no. 2, Feb. 2012, pp. 147-64, https://umj.imath.kiev.ua/index.php/umj/article/view/2562.