David Perlman, Fossils From Ethiopia May Be Earliest Human Ancestor, su news.nationalgeographic.com, National Geographic News, 12 luglio 2001. URL consultato il luglio 2009.
«Another co-author is Tim D. White, a paleoanthropologist at UC-Berkeley who in 1994 discovered a pre-human fossil, named Ardipithecus ramidus, that was then the oldest known, at 4.4 million years.»