APA (7th ed.) Citation

Dirr, M. (2011). Dirr's encyclopedia of trees and shrubs. Timber Press.

Chicago Style (17th ed.) Citation

Dirr, Michael. Dirr's Encyclopedia of Trees and Shrubs. Portland [u.a.]: Timber Press, 2011.

MLA (9th ed.) Citation

Dirr, Michael. Dirr's Encyclopedia of Trees and Shrubs. Timber Press, 2011.