00266nam a2200109Ia 4500008004100000041000800041082001900049100002000068245005100088260000900139300000800148211209s1971    xx            000 0 und d  aeng  a515.62 N71 MAR  aMARRY R SPIEGEL  aFINITE DIFFERENCES AND DIFFERENCIAL EQUATIONS   c1971  a259