1. T. Adama, N. Ameth, and N. Athoumane, Curves of constant breadth in a Walker 4-manifold, Palestine Journal of Mathematics, Vol. 12(4) (2023), 167-173.
2. S. Azimpour, A note on some properties of 4-dimensional Walker metrics, Afrika Matematika. (2021), 1-15. DOI: https://doi.org/10.1007/s 13370-021-00897-3.
3. S. Azimpour, S. Chaichi and M, Toomanian, A note on 4-dimensional locally conformally: flat Walker manifolds, IZV. NAN Armenii. Matematika. 42(5), (2007), 219-226.
4. W. Batat, G. Calvoruse, B. De Leo, On the geometry of four-dimensional Walker manifolds, Rondicontidi Matematika Serie, VII Roma 29, (2008), 163-173.
5. G. Calvoruse, and B, De Leo, Curvature properties of four-dimensional generalized symmetric spaces, J. Geom., 90, (2008), 30-46.
6. M. Chaich, E. Garc´ıa-R´ıo, and Y. Matsushita, Curvature properties of four-dimensional Walker metrics, Class. Quant. Grar., 22, (2005), 559-577.
7. M. Ciss, I. A. Kaboye and A. S. Diallo, On a family of Einstein like Walker metrics, J. Finsler Geom. Appl. 6(2) (2025), 1-11.
8. A. S. Diallo, and F. Massamba, Some properties of four-dimensional Walker manifolds, New Trends in Mathematical Sciences; Istanbul Vol. 5, Iss. 3, (2017), 253-261.DOI:10.20852/ntmsci.2017.200.
9. A. Gray, Einstein-like manifolds which are not Einstein, Geom. Dedicate, (1978), 259-280.
10. B. Rezaei, S. Masoumi and L. Ghasemnezhad, On Quasi-Einstein Kropina Metrics, J. Finsler Geom. Appl. 6(2) (2025), 92-101.
11. A. G. Walker, Cononical form for a Ricmannian Spase with a parallel fild of Null planes, Oxford, Math. (1950), 69-79.