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

• Specialist Tour de France
• Allvit
• Allvit
• Monobloc

• Publisher: New Cycling
• Document: New Cycling May 1981 - '81 Derailleur Collection
• Date: May 1981
• Derailleur brands: Huret
• Derailleurs: Huret Tour de France, Huret Monobloc, Huret Allvit (1st style), Huret Allvit