@book {Bronn1837a,
	title = {Lethaea Geognostica. Erster Band},
	year = {1837},
	pages = {1{\textendash}544},
	publisher = {E. Schweizerbart},
	organization = {E. Schweizerbart},
	address = {Stuttgart},
	keywords = {BL, TIP},
	url = {http://archive.org/details/lethaeageognosti01bron},
	author = {Bronn, Heinrich Georg}
}
@book {Bronn1838,
	title = {Lethaea Geognostica. Zweiter Band},
	volume = {2},
	year = {1838},
	pages = {769{\textendash}1346},
	publisher = {E. Schweizerbart},
	organization = {E. Schweizerbart},
	address = {Stuttgart},
	keywords = {RCBS, TIP},
	url = {http://archive.org/details/lethaeageognosti02bron},
	author = {Bronn, Heinrich Georg}
}
@book {Bronn1837,
	title = {Leth{\"a}a Geognostica. Tafeln},
	volume = {3},
	year = {1837},
	pages = {16, 47 pl.},
	publisher = {E. Schweizerbart},
	organization = {E. Schweizerbart},
	address = {Stuttgart},
	keywords = {RCBS, SDC, TIP},
	url = {http://archive.org/details/lethaeageognosti1837bron},
	author = {Bronn, Heinrich Georg}
}
