1. Bao, D., Robles, C.: On Ricci curvature and flag curvature in Finsler geometry. In: A Sample of Finsler Geomtry" MSRI series, Cambridge University Press, (2004)
2. Berwald, L.: Über die n-dimensionalen Geometrien konstanter Krümmung, in denen die Geraden die kürzesten sind. Math. Z. 30, 449–469 (1929)
3. Cheng, X., Shen, Z.: Finlser Geometry, An Approach via Randers Spaces, Mathematics Monograph Series 23
4. Li, B., Shen, Y., Shen, Z.: On a class of Douglas metrics. Studia Sci. Math. Hungar. 46(3), 355–365 (2009)
5. Mo, X., Zhu, H., Zhu, L.:On a class of Finsler gradient Ricci solitons, accepted for Proceedings of the American Mathematical Society 151(4), 1763–1773