1. General: The Copper Development Association has a top-notch website with tons of useful information.
2. General: "RICOWI Best Practices Guides for Roofing - Copper" is available on the website of the Insurance Institute for Business & Home Safety. ("RICOWI" stands for the Roofing Industry Committee on Weather Issues).
3. Chemical Compatibility of Copper: "1.3. Architectural Considerations - Weathering, Corrosion, Staining, Substrate, Solder, Sealants" is a great page on the Copper Development Association website. Well-written and very informative.
4. Historic Roofing: Copper Roofings - A Manual - Information for Architects and Roofing Contractors - Copper and Brass Research Association - (published in 1925, 25 pages).
6. Safety: See this Material Safety Data Sheet for health and safety information about copper at the Revere Copper Products website. This is only an example and other products and brands may be different.
7. Technical: Architectural details of various styles of copper roof systems can be accessed from this page at the Copper Development Association's website. Click on the type of system you're interested in at the top of the page. The drawings are done well and give you an idea of what is going on in a copper roof system.
8. Technical: "Fully Soldered Metal Roofing: More Complicated Than You Think" is an excellent article on the IIBEC (RCI, Inc.) website. Gives you a good idea of just how important expert quality workmanship is when it comes to copper roofing. From 2016.
10. Manufacturers: Copper roofing manufacturers can be found here.