Core, E. L., & Ammons, N. P. (1999). Woody plants in winter: A manual of common trees and shrubs in winter in the northeastern United States and southeastern Canada. West Virginia University Press.

Core, Earl Lemley, and Nelle P. Ammons. Woody Plants in Winter: A Manual of Common Trees and Shrubs in Winter in the Northeastern United States and Southeastern Canada. Morgantown: West Virginia University Press, 1999.

Core, Earl Lemley, and Nelle P. Ammons. Woody Plants in Winter: A Manual of Common Trees and Shrubs in Winter in the Northeastern United States and Southeastern Canada. West Virginia University Press, 1999.