Frost, J. L., Wortham, S. C., & Reifel, R. S. (2008). Play and child development (3rd ed.). Pearson/Merrill Prentice Hall.
Cita Chicago (17th ed.)Frost, Joe L., Sue Clark Wortham, i Robert Stuart Reifel. Play and Child Development. 3rd ed. Upper Saddle River, N.J: Pearson/Merrill Prentice Hall, 2008.
Cita MLA (9th ed.)Frost, Joe L., et al. Play and Child Development. 3rd ed. Pearson/Merrill Prentice Hall, 2008.
Atenció: Aquestes cites poden no estar 100% correctes.