DITCHEV, A. EXACT EFFECTIVE ENUMERATIONS OF TOTAL FUNCTIONAL STRUCTURES. Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 100, p. 35–46, 2011. Disponível em: https://stipendii.uni-sofia.bg/index.php/fmi/article/view/245. Acesso em: 23 dec. 2024.