Mačys, Juozas Juvencijus. “Geometrical Reasoning in the Determination of the Order of Factorial”. Lietuvos matematikos rinkinys 48, no. proc. LMS (December 21, 2008): 109–114. Accessed November 7, 2025. https://www.zurnalai.vu.lt/LMR/article/view/18073.