Vegetational history and climatic transition in an Eocene Intermontane Basin: Plant microfossil evidence from the Green River Formation, fossil basin, Wyoming.
Reference:
Cushman,R.A.Jr (1999)
Vegetational history and climatic transition in an Eocene Intermontane Basin: Plant microfossil evidence from the Green River Formation, fossil basin, Wyoming. NPS Paleontological Research Volume 4. Technical Report
Vol. 99 # 3 P. 66- 71