@article {1834,
	title = {Infectivity of Cryptosporidium parvum in healthy adults with pre-existing anti-C. parvum serum immunoglobulin G.},
	journal = {The American journal of tropical medicine and hygiene},
	volume = {60},
	year = {1999},
	pages = {157{\textendash}164},
	author = {Chappell, Cynthia L and Okhuysen, Pablo C and Sterling, Charles R and Wang, Constance and Jakubowski, Walter and Dupont, Herbert L}
}
@article {1835,
	title = {Virulence of three distinct Cryptospovidium parvum isolates for healthy adults},
	journal = {The Journal of infectious diseases},
	volume = {180},
	year = {1999},
	pages = {1275{\textendash}1281},
	author = {Okhuysen, Pablo C and Chappell, Cynthia L and Crabb, Joseph H and Sterling, Charles R and Dupont, Herbert L}
}
