ESTIMATES FOR THE SINGULAR SOLUTIONS OF THE 3-D PROTTER’S PROBLEM. Annual of Sofia University St. Kliment Ohridski. Faculty of Mathematics and Informatics, [S. l.], v. 96, p. 117–139, 2004. Disponível em: https://annual.uni-sofia.bg/index.php/fmi/article/view/167. Acesso em: 11 jan. 2026.