Verbatim text: Walker, J. W. and A. G. Walker. 1984. Ultrastructure of lower Cretaceous angiosperm pollen and the origin and early evolution of flowering plants. Ann. Missouri Bot. Gard. 71: 464-521.
Author: Walker, J.W., Walker, A.G.
Year: 1984
Title: Ultrastructure of lower Cretaceous angiosperm pollen and the origin and early evolution of flowering plants
Journal: Ann. Missouri Bot. Gard
Volume: 71
Pages: 464–521
BHL link: http://www.biodiversitylibrary.org/part/3957