00318nam a2200121Ia 4500082001900000100002100019245005600040260003400096300001600130490004000146500000500186700000500191  a515.35bK22.RC  aKawohl, Bernhard  aRearrangements and convexity of leval sets in PDEb  aBerlinbSpringer-Verlagc1985  a134p. Index  aLecture notes in Mathematicsv 1150  a  a