Velocity of Dislocations in Crystals T. Thomas Indiana University Mathematics Journal 1969 text pdf 10.1512/iumj.1969.18.18044 10.1512/iumj.1969.18.18044 en Indiana Univ. Math. J. 18 (1969) 571 - 583 state-of-the-art mathematics http://iumj.org/access/