I do very little model sketches these days, so yesterday I decided to go for it.
First I found a newspaper photo of a man who has somewhat sour expression. It seemed almost exaggerated, thus perfect for drawing.
Then I chose a totally different person. This young Indian is from a collection of digitalized historical photographs. I saw the link in SL Scheibe's blog, thanks for the tip! The photograph was taken by Edward S. Curtis in 1905.