Haider عأ. Geometrical invariant element’s in theory 2F- mapping between Riemannian spaces A\(_n\) which have tensors (F)\(^3\)=0. Univ. Aden J. Nat. and Appl. Sc. [Internet]. 2017 Aug. 31 [cited 2024 May 18];21(2):267-7. Available from: https://uajnas.adenuniv.com/index.php/uajnas/article/view/251