This is so awesome! Probably the best head turn-around I have seen. A lot of the others I have been looking at have problems such as being vague on certain details (like the nose on a looking-up angle) or the character looks completely different at each angle. Your has none of these problems, everything is very clear.
I don't know how times people asked if they can use this and you got use to it by now, but this is out of courtesy. So, may I use this as reference, please? I mean... I am horrible at trying to draw a person's head in an angle whether they look up or down!