[1]
“ESTIMATES FOR THE SINGULAR SOLUTIONS OF THE 3-D PROTTER’S PROBLEM”, Ann. Sofia Univ. Fac. Math. and Inf., vol. 96, pp. 117–139, Dec. 2004, Accessed: Jan. 11, 2026. [Online]. Available: https://annual.uni-sofia.bg/index.php/fmi/article/view/167