00309nam a2200121 a 450000500170000002000150001708200150003210000200004724500300006726000290009730000220012649000390014820251203110738.0  a8181283945  a512.7bSTI  aStillwell, John  aElements of number theory  aNew YorkbSpringerc2002  axi,254p.c24cm PB  aUndergraduate Texts in Mathematics