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

• Vittoria (Italy)
• XB3 (Soviet Union)
• On the top black border; 'China'
• On the black border; 'Witmy (France)'. On the photo itself; '2-speed 1928'

I think that slightly better labels might be:

• Vittoria Margherita (Italy)
• Kharkov (Ukraine - although Ukraine was, of course, part of the Soviet Union in May 1981)
• I think this may be a Dodsun (from Taiwan rather than China)
• Cyclo Witmy 2-speed (France) - I am a little suspicious about the date of 1928 for this derailleur. This seems early to me, the UK patent for the Witmy dates from 1933 and the earliest advert that I have dates from 1934.

• Publisher: New Cycling
• Document: New Cycling May 1981 - '81 Derailleur Collection
• Date: May 1981
• Derailleur brands: Cyclo, Kharkov, Vittoria, Dodsun? or Unknown Chinese brand
• Derailleurs: Vittoria Margherita, Kharkov, Dodsun, Cyclo Witmy