Hristov, Asen, and Georgi Kostadinov. “MANIFOLDS ADMITTING A STRUCTURE OF FOUR DIMENTIONAL ALGEBRA OF AFFINORS”. Ann. Sofia Univ. Fac. Math. and Inf. 103 (December 12, 2016): 89–95. Accessed November 22, 2024. https://annual.uni-sofia.bg/index.php/fmi/article/view/57.