N. Koblitz, p-adic Numbers, p-adic Analysis and Zeta-Functions, second edition, GTM 58, Springer-Verlag, 1984.
S. Lang, Algebra, GTM 211, Springer-Verlag, 2002.
J. Neukirch, Algebraic Number Theory, Springer-Verlag, 1999.
J. -P. Serre, A Course in Arithmetic, GTM 7, Springer-Verlag, 1973.
J. -P. Serre, Local Fields, GTM 67, Springer-Verlag, 1979.