@article {4981,
	title = {Contributions to the orchid flora of Thailand XII},
	journal = {Opera Bot.},
	volume = {124},
	year = {1995},
	month = {1995///},
	pages = {5 - 90},
	author = {Seidenfaden, G.}
}
@article {3176,
	title = {The genus Exacum (Gentianaceae)},
	journal = {Opera Bot.},
	volume = {84},
	year = {1985},
	month = {1985///},
	pages = {1 - 144},
	author = {Klackenberg, J.}
}
@article {2815,
	title = {Ecuadorian saprophytes, a preliminary review},
	journal = {Opera Bot.},
	volume = {92},
	year = {1987},
	month = {1987///},
	pages = {131 - 145},
	author = {Maas, P. J. M. and Maas, H.}
}
