My random translations of the photo captions, clockwise from top left are:

• SunTour GT
• SunTour V GT
• SunTour V GT
• SunTour GT

I think that the correct labels might be:

• SunTour V GT
• SunTour V GT
• SunTour V GT Luxe (1500)
• SunTour GT

• Publisher: New Cycling
• Document: New Cycling May 1981 - Derailleur Collection
• Date: May 1981
• Derailleur brands: SunTour
• Derailleurs: SunTour V GT, SunTour V GT, SunTour V GT Luxe (1500), SunTour GT