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

• Shimano 600
• Shimano 600 EX
• Shimano 600EXGT
• Shimano 600GT

I think that the correct labels might be:

• Shimano 600
• Shimano 600 EX
• Shimano 600EX GS
• Shimano 600 GS

• Publisher: New Cycling
• Document: New Cycling May 1981 - '81 Derailleur Collection
• Date: May 1981
• Derailleur brands: Shimano
• Derailleurs: Shimano 600 black (6000?), Shimano 600EX Arabesque, Shimano 600 GS (6001?), Shimano 600 EX GS Arabesque