An external approach to abstract data types I: computability on abstract data type. Annual of Sofia University St. Kliment Ohridski. Faculty of Mathematics and Informatics, [S. l.], v. 87, p. 47–59, 1995. Disponível em: https://annual.uni-sofia.bg/index.php/fmi/article/view/404. Acesso em: 14 dec. 2025.