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.
Chicago-referens (17:e uppl.)Core, Earl Lemley, och 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.
MLA-referens (9:e uppl.)Core, Earl Lemley, och 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.
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