Apple Pascal games /

by Hergert, Douglas.
Published 1981

Microsoft QuickBASIC : developing structured programs in the Microsoft QuickBASIC programming environment /

by Hergert, Douglas.
Published 1988

Microsoft quickbasic : developing structured programs in the microsoft quickbasic environment /

by Hergert, Douglas.
Published 1989

Visual Basic programming with Windows applications /

by Hergert, Douglas A.
Published 1991