APA Style
WordPerfect version 6.0 : DOS. (1993).
Utah:
WordPerfect Corporation.
Chicago Style
WordPerfect version 6.0 : DOS.
.
Utah:
WordPerfect Corporation,
1993.
Book.
MLA Style
WordPerfect version 6.0 : DOS.
.
Utah:
WordPerfect Corporation,
1993.
Book.
Turabian Style
WordPerfect version 6.0 : DOS.
Utah:
WordPerfect Corporation,
1993.
Book.