Understanding old Nikon lenses: AI, AI-S, AF and AF-S: Digital Photography Review
How to tell the difference between Nikon Pre-AI, AI and AIS lenses and how they work. - YouTube
Nikkor 50mm f/1.4 Ai-S & 50mm f/1.2 Ai-S Standard Lenses - Version History in Ai-S Nikkor- Part VI
Ran into an old friend yesterday: My Nikon 28/2.8 AIS (0.2 m close focus) - Nikon - Photo.net
Lens Adapter Ring For Nikon F (non-ai, Ai, Ais) Lens To For Canon Eos Ef Ai-eos 550d 60d 5d3 700d 7d 50d 5d2 6d Brass Silver - Lens Adapter - AliExpress