{{Cite journal| doi = 10.1371/journal.pone.0004624| issn = 1932-6203| volume = 4| issue = 2| pages = 1–7| last1 = Guilmoto| first1 = Christophe Z.| last2 = Hoàng| first2 = Xuyên| last3 = Ngo Van| first3 = Toan| title = Recent Increase in Sex Ratio at Birth in Viet Nam| journal = PLoS One| date = 2009}}