Existence Theory and Qualitative Properties of the Solutions of some First Order Quasilinear Variational Inequalities J. DiazLaurent Veron Indiana University Mathematics Journal 1983 text pdf 10.1512/iumj.1983.32.32025 10.1512/iumj.1983.32.32025 en Indiana Univ. Math. J. 32 (1983) 319 - 361 state-of-the-art mathematics http://iumj.org/access/