Gerald Mayr & Vanesa L. De Pietri (2014). “Earliest and first Northern Hemispheric hoatzin fossils substantiate Old World origin of a "Neotropic endemic"”. Naturwissenschaften. 101 (2): 143–148. doi:10.1007/s00114-014-1144-8. PMID24441712.
Gerald Mayr & Vanesa L. De Pietri (2014). “Earliest and first Northern Hemispheric hoatzin fossils substantiate Old World origin of a "Neotropic endemic"”. Naturwissenschaften. 101 (2): 143–148. doi:10.1007/s00114-014-1144-8. PMID24441712.