A Quarter Century of Unix

https://wiki.tuhs.org/lib/exe/fetch.php?media=publications:qcu.pdf

The C Programming Language

The Design and Implementation of the 4.3BSD UNIX Operating System

The Design and Implementation of the 4.4BSD Operating System

Life with Unix

http://www.tuhs.org/Archive/Documentation/Books/Life_with_Unix.pdf

Lions’ Commentary on UNIX 6th Edition

The Unix Programming Environment

https://web.archive.org/web/20170720132901/https://cs.uwec.edu/~buipj/teaching/cs.388.s14/static/pdf/upe.pdf

https://wiki.tuhs.org/doku.php?id=publications:books