Interactive Systems Corporation (English Wikipedia)

Felton, W. A.; Miller, G. L.; Milner, J. M. (1984). "A UNIX System Implementation for System/370" (PDF). AT&T Bell Laboratories Technical Journal. 63 (8).

books.google.com (Global: 3^rd place; English: 3^rd place)

Krause, Carolyn; Lyon, Barbara; Zucker, Alex; Clark, Bill (1981). "Winter 1981 Oak Ridge National Laboratory Review". Oak Ridge National Laboratory Review. 14 (1): 18.
Babcock, Charles (1986-01-27). "IBM unveils RISC system". Computerworld. Vol. XX, no. 4. pp. 1, 8. Retrieved 2025-05-29.
Patricia Keefe (July 6, 1986). "IBM, Locus to co-develop PS/2 AIX system". Computerworld: The Newsweekly of Information Systems Management. Computerworld: 8. ISSN 0010-4841.
James R. Groff; Paul N. Weinberg (13 November 1984). "IBM's UNIX formula for your PC". PC Mag. Ziff Davis, Inc.: 159–160. ISSN 0888-8507.
McMahon, Marilyn; Putnam, Robert (1984-04-02). "A First Look at PC-IX". InfoWorld. pp. 39–42. Retrieved 25 February 2016.
Zachmann, Mark S. (12 June 1984). "A Venerable UNIX". PC Magazine. Vol. 3, no. 11. New York: Ziff Davis. p. 246. ISSN 0888-8507. Retrieved 2021-03-13 – via Google Books. VenturCom's implementation of UNIX Version 7, quietly released a year before PC/IX, is a competent and nearly complete version with good documentation.
Robin Webster (10 July 1984). "Gurus powwow on UNIX, but few applications exist". PC Mag. Ziff Davis, Inc.: 43. ISSN 0888-8507.
Bill Machrone (29 May 1984). "Fact or Fiction?". PC Magazine: 84. ISSN 0888-8507.
Vaughan-Nichols, Steven J. (15 June 1993). "Interactive Unix". PC Magazine. p. 240.

"Peter Norton entered Unix computer software market". The Los Angeles Business Journal. 1990-05-07. Archived from the original on 2008-03-06.

Segue Software. "Form 10-K: Annual Report". SEC.gov. United States Securities and Exchange Commission. Retrieved 24 June 2025. The Company contracted with third parties to assist in the work of porting the Lotus 1-2-3 spreadsheet software to the UNIX operating system.

Sten A. O. Thore (31 October 1995). The diversity, complexity, and evolution of high tech capitalism (PDF). Kluwer Academic Publishers. p. 78. ISBN 9780792396390. Archived from the original (PDF) on 2012-02-17.

Salus, Peter H. (2005). "Chapter 15. Commercial UNIXes to BSDI". The Daemon, the Gnu and the Penguin. Groklaw. Archived from the original on May 5, 2010.
Sten A. O. Thore (31 October 1995). The diversity, complexity, and evolution of high tech capitalism (PDF). Kluwer Academic Publishers. p. 78. ISBN 9780792396390. Archived from the original (PDF) on 2012-02-17.
"Peter Norton entered Unix computer software market". The Los Angeles Business Journal. 1990-05-07. Archived from the original on 2008-03-06.
Peter H. Salus, "Nearly 20 Years ago in U[SE]NIX," ;login: 28(6), December 2003 [1]

Patricia Keefe (July 6, 1986). "IBM, Locus to co-develop PS/2 AIX system". Computerworld: The Newsweekly of Information Systems Management. Computerworld: 8. ISSN 0010-4841.
James R. Groff; Paul N. Weinberg (13 November 1984). "IBM's UNIX formula for your PC". PC Mag. Ziff Davis, Inc.: 159–160. ISSN 0888-8507.
Zachmann, Mark S. (12 June 1984). "A Venerable UNIX". PC Magazine. Vol. 3, no. 11. New York: Ziff Davis. p. 246. ISSN 0888-8507. Retrieved 2021-03-13 – via Google Books. VenturCom's implementation of UNIX Version 7, quietly released a year before PC/IX, is a competent and nearly complete version with good documentation.
Robin Webster (10 July 1984). "Gurus powwow on UNIX, but few applications exist". PC Mag. Ziff Davis, Inc.: 43. ISSN 0888-8507.
Bill Machrone (29 May 1984). "Fact or Fiction?". PC Magazine: 84. ISSN 0888-8507.