Young, S. L. (2011). Craving earth: Understanding pica : the urge to eat clay, starch, ice, and chalk. Columbia University Press.
Chicago-viite (17. p.)Young, Sera L. Craving Earth: Understanding Pica : The Urge to Eat Clay, Starch, Ice, and Chalk. New York: Columbia University Press, 2011.
MLA-viite (9. p.)Young, Sera L. Craving Earth: Understanding Pica : The Urge to Eat Clay, Starch, Ice, and Chalk. Columbia University Press, 2011.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.