Reminiscences of prof. Dolaptchiev. Annual of Sofia University St. Kliment Ohridski. Faculty of Mathematics and Informatics, [S. l.], v. 88, p. 51–72, 1996. Disponível em: https://annual.uni-sofia.bg/index.php/fmi/article/view/378. Acesso em: 15 dec. 2025.