@article {311293,
	title = {Why are there no persisting hybrids of humans with Denisovans, Neanderthals, or anyone else?},
	journal = {Proceedings of the National Academy of Sciences},
	volume = {113},
	number = {17},
	year = {2016},
	pages = {E2354-E2354},
	publisher = {National Acad Sciences},
	isbn = {0027-8424},
	url = {http://www.pnas.org/content/113/17/E2354},
	author = {Ajit Varki}
}
