00339nam a2200121Ia 4500082002100000100001600021245006400037260002600101300002300127500005700150500000500207700000500212  a515.35bSa129.BE  aSagan, Hans  aBoundary and eigen value problems in mathematical physicsb  aNew YorkbDoverc1989  axviii, 381p. Index  a"Originally published in 1961 by John Wiley & sons".  a  a