Pickering, Travis Rayne: Rough and tumble: aggression, hunting, and human evolution. Berkeley 2013. Internet: https://books.google.de/books?id=D_Uqv1XqBlkC&printsec=frontcover&dq=Rough+and+Tumble.+Aggression,+Hunting+and+Human+Evolution.&hl=en&sa=X&ved=0ahUKEwjwoo_6sbDTAhVHVxoKHXyHBSgQ6AEIJDAA#v=onepage&q&f=false. Zuletzt geprüft am: 19.4.2017.