On G-Convergence of Elliptic Operators Leon Simon Indiana University Mathematics Journal 1979 text pdf 10.1512/iumj.1979.28.28041 10.1512/iumj.1979.28.28041 en Indiana Univ. Math. J. 28 (1979) 587 - 594 state-of-the-art mathematics http://iumj.org/access/