Halic, Gheorghe, and Eduard Halic. “Extensions of Certain Relations of the Classical Analysis”. Rev. Anal. Numér. Théor. Approx. 34, no. 1 (February 1, 2005): 63–69. Accessed September 3, 2025. https://www.ictp.acad.ro/jnaat/journal/article/view/2005-vol34-no1-art7.