Rick Riordan (2013). “Demigods and Monsters: Your Favorite Authors on Rick Riordan's Percy Jackson and the Olympians Series”, p.115, BenBella Books, Inc.
Rick Riordan (2013). “Demigods and Monsters: Your Favorite Authors on Rick Riordan's Percy Jackson and the Olympians Series”, p.111, BenBella Books, Inc.