@article {620,
	title = {Seed coat anatomy of Ceratozamia mexicana (Cycadales)},
	journal = {The Botanical Review},
	volume = {70},
	year = {2004},
	pages = {24-38},
	chapter = {24},
	author = {S{\'a}nchez-Tinoco, Mar{\'\i}a Ydelia and Engleman, E. Mark}
}
@article {573,
	title = {Defining the gigantopterid concept: a reinvestigation of Gigantopteris (Megalopteris) nicotianaefolia Schenck and its taxonomic implications},
	journal = {Palaeontology},
	volume = {47},
	year = {2004},
	pages = {1339-1361},
	chapter = {1339},
	author = {Glasspool, I.G. and Hilton, Jason and Collinson, M.E. and Wang, S.J.}
}
