@article {552,
	title = {Molecular phylogeny of extant gymnosperms and seed plant evolution: analysis of nuclear 18S r RNA sequences},
	journal = {Molecular Biology and Evolution},
	volume = {14},
	year = {1997},
	pages = {56-68},
	chapter = {56},
	author = {Chaw, S.M. and Zharkikh, A. and Sung, H.M. and Lau, T.C. and Li, W.H.}
}
