1.
Masal’tsevLA. On Isometric Immersion of Three-Dimensional Geometries $SL_2$, $Nil$ and $Sol$ into a Four-Dimensional Space of Constant Curvature. Ukr. Mat. Zhurn. [Internet]. 2005Mar.25 [cited 2024Nov.22];57(3):421–426. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/3609