Laetoli Footprints Preserve Earliest Direct Evidence of Human-Like Bipedal Biomechanics Raichlen, David A. ; Gordon, Adam D. ; Harcourt-Smith, William E. H. ; Foster, Adam D. ; Haas, Wm. Randall Abstract Publication: PLoS ONE Pub Date: March 2010 DOI: 10.1371/journal.pone.0009769 Bibcode: 2010PLoSO...5.9769R