[1]
“On a generalization of the Jacobi operator in the Riemannian geometry”, Ann. Sofia Univ. Fac. Math. and Inf., vol. 86, no. 1, pp. 27–34, Dec. 1994, Accessed: Jan. 11, 2026. [Online]. Available: https://annual.uni-sofia.bg/index.php/fmi/article/view/432