Preliminary report of Upper Cretaceous angiosperm reproductive organs from Sweden and their level of organization. (In: Historical Perspectives of Angiosperm Evolution.)
Reference:
Friis,E.M. (1984)
Preliminary report of Upper Cretaceous angiosperm reproductive organs from Sweden and their level of organization. (In: Historical Perspectives of Angiosperm Evolution.) Annals of the Missouri Botanical Garden
Vol. 71 # 2 P. 403- 418