Andrew Loomis books
This is a link to all of Andrew Loomis’s books, which were printed in the 20th century but provide excellent tips on perspective, anatomy, balance, etc… http://alexhays.com/loomis/
I get a lot of the tuts/references I post here from archived posts on /ic/, so I was happy I recently found this! It’s a collection of a lot of links posted on /ic/ that encompasses a lot topics like anatomy, composition, painting, etc.
Happy drawing, good luck!