00321nam a2200121 a 450000500170000002000150001708200180003210000230005024500340007326000290010730000270013649000360016320251203110844.0  a0898713706  a515.7242bLAN  aLanczos, Cornelius  aLinear differential operators  aPhiladelphiabSiamc1996  axviic564p.c24 cm. PB  aClassics in applied mathematics