Popivanov, N. and Popov, T. (2004) “ESTIMATES FOR THE SINGULAR SOLUTIONS OF THE 3-D PROTTER’S PROBLEM”, Ann. Sofia Univ. Fac. Math. and Inf, 96, pp. 117–139. Available at: https://ftl5.uni-sofia.bg/index.php/fmi/article/view/167 (Accessed: 24 November 2024).