Artistic Anatomy- Paul Richter (in French on a French website)
This book is a priceless tool. I suggest buying it in English. However, it is on this French website for free.
Pay attention to this, I do not care if you are learning how to draw, learning how to sculpt, or learning zbrush! If you are in a figurative art field, you need this resource. Email if you have any questions or need help.