APA (7th ed.) Citation

Lewis, D. (1978). The secret language of your child: How children talk before they can speak. St. Martin's Press.

Chicago Style (17th ed.) Citation

Lewis, David. The Secret Language of Your Child: How Children Talk Before They Can Speak. New York: St. Martin's Press, 1978.

MLA (9th ed.) Citation

Lewis, David. The Secret Language of Your Child: How Children Talk Before They Can Speak. St. Martin's Press, 1978.