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

• Eagle II
• Eagle Schwinn
• Positron
• Eagle Schwinn

I think that the correct labels might be:

• Shimano Eagle II (EG10)
• Schwinn GT100
• Shimano Positron
• Shimano Schwinn GT120

• Publisher: New Cycling
• Document: New Cycling May 1981 - '81 Derailleur Collection
• Date: May 1981
• Derailleur brands: Shimano, Schwinn
• Derailleurs: Shimano Eagle II (EG10), Shimano Positron (DG100 1st style), Schwinn GT100, Schwinn GT120