Can you help me find an art print for our Son's Room?

We had to take our baby girl to the University of Iowa Hospitals and Clinics for testing. On the floor where the pediatric department was, there was a really neat huge poster of a treehouse! We read the description next to it and it is from the book Jungle Gym Jitters written and illustrated by Chuck Richards. I want a poster like it for our son's camping themed room! Anyone know where I can find it? It doesn't have to be quite that big, but size doesn't really matter, I love the print!