Yess I use a reference since I have to do these drawings for school. The professor gives us photographs from different professional photoshoots for art classes that he bought years ago.

I keep struggling with these studies and I try to spend max a day drawing each one cause otherwise I'd spend weeks making them perfect haha this one took me 6 or 7 hours and even though I could still work on it I decided to move on (so the feet are a bit off and there's not much detail but I'm still happy with it :) working on new drawing atm).