1. Sur une classe remarquable d’espaces de Riemannian;Cartan;Bull. Soc. Math. Fr.,1926
2. On conformally symmetric spaces;Chaki;Indian J. Math.,1963
3. On Ruse’s spaces of recurrent curvature;Walker;Proc. Lond. Math. Soc.,1951
4. On a Riemannian space with recurrent conformal curvature;Adati;Tensor,1967
5. On pseudo symmetric manifolds;Chaki;Ann. Stiint. Univ. Alexandru Ioan I Cuza Iasi,1987