Author's Note: Pencil@paper (I hope you don't mind sketches) :)
17 years ago I was kinda obsessed by horses. I collected pics, stories, read a lot about horses origin, breed, training, anatomy and drew them a lot. I did not really need any references to do it. But this time I had to dig out my old horse breeding magazines - just to specify veins direction and nostrils structure. That is all. There is NO particular picture that I used for the basis, so I can't link to the source, sorry :)