Still too lazy to go outside, although the weather is fine. Stan Prokopenko often recommends studying George Bridgman to improve line quality and anatomy. I don't know what "studying" means, so I just copied the first page out of his anatomy book.
Things I learned: 1. I don't really own a "pen" pen, like Bridgman probably used, just fineliners, and that makes a difference on line weight. Also I think he used rougher paper.
2. I like his curves. I should probably put more effort into ghosting curves and circles.

reference at
https://archive.org/details/GeorgeB.BridgmanConstructiveAnatomy/page/n11/mode/1up
Don't know what "studying" a master means, but I tried to copy a page from george bridgman