APA (7th ed.) Citation

Wahl, J., & Wahl, S. (1976). I can count the petals of a flower. National Council of Teachers of Mathematics.

Chicago Style (17th ed.) Citation

Wahl, John, and Stacey Wahl. I Can Count the Petals of a Flower. Reston, Va.: National Council of Teachers of Mathematics, 1976.

MLA (9th ed.) Citation

Wahl, John, and Stacey Wahl. I Can Count the Petals of a Flower. National Council of Teachers of Mathematics, 1976.