APA (7th ed.) Citation

Gelderen, C. J. v., & Gelderen, D. M. v. (2004). Encyclopedia of hydrangeas. Timber Press.

Chicago Style (17th ed.) Citation

Gelderen, C. J. van, and D. M. van Gelderen. Encyclopedia of Hydrangeas. Portland, Or.: Timber Press, 2004.

MLA (9th ed.) Citation

Gelderen, C. J. van, and D. M. van Gelderen. Encyclopedia of Hydrangeas. Timber Press, 2004.