@article {89,
	title = {Ultrastructural characters of the pollen grains of African Annonaceae and their significance for the phylogeny of primitive angiosperms (first part)},
	journal = {Pollen \& Spores},
	volume = {22},
	year = {1980},
	pages = {267{\textendash}342},
	author = {Le Thomas, A.}
}
@article {90,
	title = {Ultrastructural characters of the pollen grains of African Annonaceae and their significance for the phylogeny of primitive angiosperms (second part)},
	journal = {Pollen \& Spores},
	volume = {23},
	year = {1981},
	pages = {1-36},
	author = {Le Thomas, A.}
}
