Kiosak, Volodymyr, Aleksandr Savchenko, and Galina Kovalova. “Geodesic Mappings of Compact Quasi-Einstein Spaces, I”. Proceedings of the International Geometry Center 13, no. 1 (June 4, 2020): 35-48. Accessed June 28, 2026. https://journals.ontu.edu.ua/index.php/geometry/article/view/1711.