Improved age control on early Homo fossils from the upper Burgi Member at Koobi Fora, Kenya - Joordens, Joséphine C. A.; Dupont-Nivet, Guillaume; Feibel, Craig S.; Spoor, Christiaan Frederik; Sier, Mark Jan; Lubbe, H. J. L. van der; Nielsen, Trine Kellberg; Knul, Monika V.; Davies, Gareth R.; Vonhof, Hubert B. (2013)