McClure, M.S., & Hare, J.D. 1984 Foliar terpenoids in Tsuga species and the fecundity of scale insects.. Oecologia 63: 185-193.

Notes: Fiorinia externa, Nuculaspis tsugae; analysis of foliar terpenoids may provide basis for predicting relative susceptibility of Tsuga spp. to attack by F. externa and N. tsugae.