K. N. King   "C Programming: A Modern Approach"

Harbison and Steele   "C: A Reference Manual"

Kernighan and Ritchie   "C Programming Language"

The current standard for Programming Language C is ISO/IEC 9899:1999, published 1999-12-01. However, most compilers do not include many of the changes / additions that are made by the new standard. The original ANSI C standard approved in 1989 is still what most compilers conform to. The new standard is referred to as ANSI 99.

The latest publicly available version of the standard is the FCD 9899, SC22 N2794. You can download it here.

ISO/IEC JTC1/SC22/WG14 is the international standardization working group for the programming language C. Their web site can be found here:

http://std.dkuug.dk/JTC1/SC22/WG14/

Approved standards information can be found here:

http://std.dkuug.dk/JTC1/SC22/WG14/www/standards