XIONG, sun. The zeros of f^{n}f^(k)-a and normal families of meromorphic functions. Tamkang Journal of Mathematics, [S. l.], v. 51, n. 2, p. 137-144, 2020. DOI: 10.5556/j.tkjm.51.2020.3041. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/3041. Acesso em: 26 sep. 2020.