AIP featuring: gambierpipes.com
This is the wonderful website of Arthur van Esveld, a dutch collector of Gambier clay pipes. His collection is probably the largest of this kind in the world. Arthur has made his full collection digitally available through his website. For each pipe he gives the various publication dates, dimensions, description and a brief history of the topic depicted on each pipe.
His website is a great resource for other collectors, and genuinely fun to browse through.