Piętka, M. (1990). The estimation of the operational functions of the type exp[(Σ_{ν=1}^nβ_νs^{p_ν})λ].
Annales Mathematicae Silesianae
,
4
, 25–34. Retrieved from https://journals.us.edu.pl/index.php/AMSIL/article/view/14290