00253nam a2200109Ia 4500008004100000041000800041082000800049100001500057245003100072260003200103300000800135211209s1980 xx 000 0 und d aeng aDUF aDUFFIJ W J aELECTRICITY AND MAGNETISM  aNEW YORKbMCGR@W-HILLc1980 a404