Solution of Some Problems in the Exact Theory of Visco-Elasticity R. Rivlin Indiana University Mathematics Journal 1956 text pdf 10.1512/iumj.1956.5.55004 10.1512/iumj.1956.5.55004 en Indiana Univ. Math. J. 5 (1956) 179 - 188 state-of-the-art mathematics http://iumj.org/access/