The UNIX Time-Sharing System http://www.alcatel-lucent.com/bstj/vol57-1978/articles/bstj57-6-1905.pdf UNIX Time-Sharing System: A Retrospective http://www.alcatel-lucent.com/bstj/vol57-1978/articles/bstj57-6-1947.pdf UNIX Time-Sharing System: The C Programming Language http://www.alcatel-lucent.com/bstj/vol57-1978/articles/bstj57-6-1991.pdf