M.D., Christopher Vaughan, and Stuart Brown. Play: How It Shapes the Brain, Opens the Imagination, and Invigorates the Soul. 1 ed. New York: Avery, 2009. Print.

Gever Tulley, author of 50 Dangerous Things you should let your children do, gave 2 different TED talks: Gever Tully teaches life lessons through tinkering and 5 Dangerous Things for Kids