I am not sure how many people are familiar with the work of Paul Calle. His early years were spent as an illustrator working at NASA. He did the artwork for the Apollo stamps and many incredible paintings. I had the pleasure of seeing some of his work at Gilcrease Museum in Tulsa Ok. His pencil work is so amazing that on many Jobs he would turn in a rough for clients to see and they would print the rough. He also has a book about drawing.. The pencil. Found the book on Amazon although it was much cheaper 20 years ago. I could not find an official Calle website. Here is a link to see some of his work.