Sierpinski, W. “Sur Quelques Problemes Concernant Les Suites Infinies D’Ensembles Infinis De Nombres Naturels”. The Journal of the Indian Mathematical Society 24, no. 3-4 (December 1, 1960): 551–555. Accessed May 3, 2024. https://informaticsjournals.com/index.php/jims/article/view/16931.