- Jon "maddog" Hall talks Unix and Linux history
2018 - Jon Hall - Unix and Multics
Last updated 12/13/16 - Tom Van Vleck 
The Evolution of C Programming Practices: A Study of the Unix Operating System 1973–2015 May 2016 - Diomidis Spinellis, Panos Louridas, Maria Kechagia- The Strange Birth and Long Life of Unix
11/28/2011 - Warren Toomey - The Single UNIX Specification History & Timeline
2004 - The OpenGroup - UNIX History & Timeline
2003 - Eric S. Raymond - An Interview with Brian Kernighan
July 2000 - Mihai Budiu - Twenty Years of Berkeley Unix
1999 - Marshall Kirk McKusick1 - A Research UNIX Reader: Annotated Excerpts from the Programmer's Manual, 1971-1986
1987 - M. Douglas McIlroy - A History of UNIX before Berkeley: UNIX Evolution: 1975-1984
1984 - Ian F. Darwin, Ian Darwin, Geoffrey Collyer - Program Design in the UNIX Environment
1983 - Rob Pike, Brian W. Kernighan - The UNIX System: Making Computers More Productive
1982 - Bell Laboratories - UNIX: Making Computers Easier To Use
1982 - Bell Laboratories - The Evolution of the Unix Time-sharing System
09/10/1979 - Dennis M.Ritchie - The Unix Time-sharing System
July 1974 - Dennis M.Ritchie, Ken Thompson
[1]: It's chapter 3 of Open Sources: Voices from the Open Source Revolution book, edited by O'Reilly in 1999.