1. Chamberlain J.L., Bush R., Hammett A.L. and Araman P.A. 2002. Managing for nontimber products. J. For., Jan/Feb. pp. 8–14.
2. Emery M.R. 2002. Historical overview of nontimber forest product uses in the Northeastern United States. In: Jones E.T. etal (ed.) Nontimber Forest Products in the United States. University Press of Kansas, pp. 3–25.