Also see Edge Metal.
1. General: A lot of very good information about parapet wall coping can be found in this article, “BSI-050: Parapets—Where Roofs Meet Walls”, by Joseph Lstiburek. Available on the Building Science Corporation website.
2. Building Codes: “R903.2 Flashing” and "R903.3 Coping" from the 2015 International Residential Code and “1503.2 Flashing” and "1503.3 Coping" from the 2018 International Building Code. Both available on the UpCodes website.
3. Technical: "Architectural Fascia and Coping Wind Tests Report" is a SMACNA Technical Resources Bulletin from 2017 that describes wind uplift testing on custom-fabricated fascia and coping architectural elements constructed in accordance with the SMACNA’s Architectural Sheet Metal Manual. It tells you the maximum sustained load, in pounds, that various types of properly-installed edge metal could withstand before failing.
4. Technical: Technical Notes 36A - Brick Masonry Details, Caps and Copings, Corbels and Racking Rev [Sept./Oct. 1981] (Reissued February 2001) is an excellent source of information about masonry wall copings. Available on the website of the Brick Industry Association.
7. Technical: See here for technical information about clay wall coping. That's at the website of the Logan Clay Products Company.