On the Subharmonicity and Plurisubharmonicity of Geodesically Convex Functions R. GreeneH. Wu Indiana University Mathematics Journal 1973 text pdf 10.1512/iumj.1973.22.22052 10.1512/iumj.1973.22.22052 en Indiana Univ. Math. J. 22 (1973) 641 - 653 state-of-the-art mathematics http://iumj.org/access/