A. Bobrowski, “The Widder-Arendt theorem on inverting of the Laplace transform, and its relationships with the theory of semigroups of operators”, MFAT, vol. 3, no. 4, pp. 1–39, Dec. 1997, Accessed: Dec. 19, 2025. [Online]. Available: https://zen.imath.kiev.ua/index.php/mfat/article/view/46