[1] Besse A. L.: Manifolds all of whose Geodesies are Closed. Springer-Verlag, Berlin Heidelberg New York, 1978. MR 0496885

[2] Gray A., Willmore T. J.: Mean-value theorems for Riemannian manifolds. Proc. Roy. Soc. Edinburgh 92 A (1982), 343-364. MR 0677493 | Zbl 0495.53040

[3] Kowalski O.: The second mean-value operator on Riemannian manifolds. in Proceedings of the CSSR-GDR-Polish Conference on Differential Geometry and its Applications, Nové Město 1980, pp. 33-45, Universita Karlova Praha, 1982. MR 0663211

[4] Kowalski O.: Normal forms of the Laplacian and its iterations in the symmetric spaces of rank one. Simon Stevin, Quart. J. Pure. Applied Math. 57 (1983), 215-223. MR 0721434 | Zbl 0518.53053

[5] Kôzaki M.: On mean value theorems for small geodesic spheres in Riemannian manifolds. preprint. MR 1179316

[6] Kôzaki M., Ogura Y.: On geometric and stochastic mean values for small geodesic spheres in Riemannian manifolds. Tsukuba J. Math. 11 (1987), 131-145. MR 0899727

[7] Ruse H. S., Walker A. G., Willmore T. J.: Harmonic Spaces. Edizioni Cremonese, Roma, 1961. MR 0142062 | Zbl 0134.39202

[8] Watanabe Y.: On the characteristic function of harmonic Kählerian spaces. Tohoku Math. J. 27 (1975), 12-24. MR 0365439 | Zbl 0311.53068