Cita APA (7a ed.)

Sin autor & AT&T. (1990). UNIX System V, release 4: OPEN LOOK graphical user interface user's guide. [S.n.].

Cita Chicago Style (17a ed.)

Sin autor y AT&T. UNIX System V, Release 4: OPEN LOOK Graphical User Interface User's Guide. Englewood Cliffs: [S.n.], 1990.

Cita MLA (9a ed.)

Sin autor y AT&T. UNIX System V, Release 4: OPEN LOOK Graphical User Interface User's Guide. [S.n.], 1990.