Zieliński, M. “Cardinality of the Sets of All Bijections, Injections and Surjections”. Annales Universitatis Paedagogicae Cracoviensis | Studia Ad Didacticam Mathematicae Pertinentia, vol. 11, Dec. 2019, pp. 143-51, doi:10.24917/20809751.11.8.