Ganchev, Georgi, and Vesselka Mihova. 2015. “A CLASSIFICATION OF CONFORMALLY FLAT RIEMANNIAN MANIFOLDS LOCALLY ISOMETRIC TO HYPERSURFACES IN EUCLIDEAN OR MINKOWSKI SPACE”. Ann. Sofia Univ. Fac. Math. And Inf. 102 (December):109-32. https://annual.uni-sofia.bg/index.php/fmi/article/view/66.