@article {4704,
	title = {Self-fertilization versus cross-fertilization in two planorbid species, Planorbarius corneus (Linnaeus) and Planorbis planorbis (Linnaeus).},
	journal = {The Veliger},
	volume = {38},
	year = {1995},
	pages = {252-258},
	author = {Katherine Costil and Daguzan, Jacques}
}
