APA Style

Aker, S., Karlin, B. (1990). What comes in 2's, 3's, & 4's? . New York, USA: Scholastic Inc.

MLA Style

Aker, Suzanne., Karlin, Bernie. "What comes in 2's, 3's, & 4's?". New York, USA: Scholastic Inc, 1990. Text.