Ninova, Julia, and Vesselka Mihova. “COMPOSITION OF INVERSE PROBLEMS WITH A GIVEN LOGICAL STURCTURE”. Ann. Sofia Univ. Fac. Math. and Inf. 101 (December 12, 2013): 167–181. Accessed January 15, 2025. https://admin.uni-sofia.bg/index.php/fmi/article/view/237.