1. G. D. Amman, and R. L. Palerico, 1967 : Symptoms of infestation the balsam wooly aphid displayed by Fraser fir and Bracted balsam fir . USDA Forest Service Research Note SE-85.
2. W. L. Baker, 1972 : Eastern forest insects . USDA Forest Service Misc. Publ. 1175.
3. NEW INFORMATION CONCERNING BALSAM FIR DECAYS IN EASTERN NORTH AMERICA