Free Boundary Problems for Parabolic Equations II. Evaporation or Condensation of a Liquid Drop Avner Friedman Indiana University Mathematics Journal 1960 text pdf 10.1512/iumj.1960.9.59002 10.1512/iumj.1960.9.59002 en Indiana Univ. Math. J. 9 (1960) 19 - 66 state-of-the-art mathematics http://iumj.org/access/