I´ve been doing these studies from Glenn Vilppu´s videos from a couple of weeks now; he teaches quite fantastically. His method is a little bit different from the classical approach in that he contains/draws the volumes first, instead of drawing the contours/outlines. By drawing the volumes, one begins to visualize the 3-d form that one is attempting to draw, easily, and the contours of these volumes automatically become the outlines of the form. This approach has a major advantage in that difficult foreshortened views of figures and limbs become quite simple to draw. He also explains the muscles and muscle groups so beautifully from all possible viewpoints. Learning anatomy has become fun and too too exciting for me!!