@book {7865,
	title = {Pal{\ae}ontology},
	series = {Geological Survey of Illinois},
	volume = {2},
	year = {1866},
	note = {Have 339-341, pl.37},
	publisher = {Authority of the Legislature of Illinois},
	organization = {Authority of the Legislature of Illinois},
	address = {Chicago},
	keywords = {bivalvia, mollusca, monopteria, paleontology, pterinea, pterioida, pterioidea, taxonomy},
	author = {Worthen, A. H.}
}
@book {1697,
	title = {Pal{\ae}ontology},
	series = {Geological Survey of Illinois},
	volume = {2},
	year = {1866},
	publisher = {Authority of the Legislature of Illinois},
	organization = {Authority of the Legislature of Illinois},
	address = {Chicago},
	keywords = {bivalvia, mollusca, monopteria, paleontology, pterinea, pterioida, pterioidea, taxonomy},
	author = {Worthen, A. H.}
}
