- Erwin, D.M., and H.E. Schorn. 2000. Revision of Lyonothamnus A. Gray (Rosaceae) from the Neogene of western North America. International Journal of Plant Sciences 161(1):179-193.
- Schorn, H.E., and D.M. Erwin. 2000. The impression record history and ecological diversification of Pseudotsuga Carriere (Pinaceae) in western North America during the later half of the Cenozoic. Botany 2000, Portland, Oregon. Abstract. Read it