Cita APA (7a ed.)

Crystal, D. (1986). Listen to your child: Parent's guide to children's language. Penguin.

Cita Chicago Style (17a ed.)

Crystal, David. Listen to Your Child: Parent's Guide to Children's Language. London [etc.]: Penguin, 1986.

Cita MLA (9a ed.)

Crystal, David. Listen to Your Child: Parent's Guide to Children's Language. Penguin, 1986.