PIĘTKA, Marek. A note on the increase of the operational function exp(λΣ_{k=1}^{n}A_{k}s^{p_k}). Annales Mathematicae Silesianae, [S. l.], v. 3, p. 107–114, 1990. Disponível em: https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/14309. Acesso em: 7 may. 2025.