The status of certain families of the Amentiferae during the Middle Eocene and some hypotheses regarding the evolution of wind pollination in Dicotyledonous angiosperms.
Reference:
Crepet,W.L. (1981)
The status of certain families of the Amentiferae during the Middle Eocene and some hypotheses regarding the evolution of wind pollination in Dicotyledonous angiosperms. Paleobotany,Paleoecology and Evolution. (Karl J.Niklas,editor). Praeger, New York
Vol. 1 P. 103- 128