1. Cao H.D.: Recent progress on Ricci solitons. In: Ji, L., Li, P., Schoen, R., Simon, L. (eds.) Recent Advances in Geometric Analysis, Advanced Lectures in Mathematics, vol. 11, pp. 1–38. International Press, Somerville, MA (2010)
2. Centore P.: Finsler Laplacians and minimal-energy maps. Internat. J. Math. 11(1), 1–13 (2000)
3. Chen Q., Jost J., Wang G.: A maximum principle for generalizations of harmonic maps in Hermitian, affine, Weyl and Finsler geometry, Preprint (2011)
4. Cheng S.Y.: Liouville theorem for harmonic maps, geometry of the Laplace operator. In: Proceedings of the Symposium in Pure Mathematics. University of Hawaii, Honolulu, Hawaii, 1979, pp. 147–151, Proceedings of the Symposium in Pure Mathematics, XXXVI, American Mathematical Society, Providence, RI (1980)
5. Choi H.: On the Liouville theorem for harmonic maps. Proc. Amer. Math. Soc. 85, 91–94 (1982)