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

• Constrictor (UK)
• On the black border; 'LAS (France)'. On the photo itself; '2-speed 1920'
• On the black border; 'Le Chemineau (France)'. On the photo itself; '1912'
• Erlotti (Italy)

• Publisher: New Cycling
• Document: New Cycling May 1981 - '81 Derailleur Collection
• Date: May 1981
• Derailleur brands: Chemineau, Constrictor, As, Erlotti
• Derailleurs: Constrictor, L'As 2-speed, Le Chemineau, Erlotti