Brian W. Kernighan: Programming in C: A Tutorial
This ``tutorial'' is presented as a historical document, not as a tutorial. Although it has lost little of its didactic value, it describes a language that C compilers today do no longer understand: the C of 1974, four years before Kernighan and Ritchie published the first edition of "The C Programming Language".
Primeval C: two very early compilers
Very early C compilers and language.
The Development of the C Language
Article by Dennis M. Ritchie. History C programming language.