Uniqueness of Solutions to Hyperbolic Conservation Laws Ronald DiPerna Indiana University Mathematics Journal 1979 text pdf 10.1512/iumj.1979.28.28011 10.1512/iumj.1979.28.28011 en Indiana Univ. Math. J. 28 (1979) 137 - 188 state-of-the-art mathematics http://iumj.org/access/