Admissibility Criteria for Hyperbolic Conservation Laws Joseph ConlonTai-Ping Liu Indiana University Mathematics Journal 1981 text pdf 10.1512/iumj.1981.30.30050 10.1512/iumj.1981.30.30050 en Indiana Univ. Math. J. 30 (1981) 641 - 652 state-of-the-art mathematics http://iumj.org/access/