Lyapounov Convexity Theorem and Riemann-Type Integrals Z. Artstein Indiana University Mathematics Journal 1976 text pdf 10.1512/iumj.1976.25.25056 10.1512/iumj.1976.25.25056 en Indiana Univ. Math. J. 25 (1976) 717 - 724 state-of-the-art mathematics http://iumj.org/access/