Коновенко, Надежда, and Ирина Курбатова. “Special Classes of Pseudo-Riemannian Spaces With F-Structure That Admit 2F-Planar Mappings”. Proceedings of the International Geometry Center 11, no. 4 (April 1, 2019): 18-34. Accessed August 11, 2026. https://journals.ontu.edu.ua/index.php/geometry/article/view/1304.