APA (7th ed.) Citation

Ziefert, H., & Demarest, C. L. (1999). I need a valentine!: A lift-the-flap story. Little Simon.

Chicago Style (17th ed.) Citation

Ziefert, Harriet, and Chris L. Demarest. I Need a Valentine!: A Lift-the-flap Story. New York, N.Y.: Little Simon, 1999.

MLA (8th ed.) Citation

Ziefert, Harriet, and Chris L. Demarest. I Need a Valentine!: A Lift-the-flap Story. Little Simon, 1999.