@article {301651, title = {Three-dimensional limb joint mobility in the early tetrapod Ichthyostega}, journal = {Nature}, volume = {486}, year = {2012}, pages = {523-526}, url = {http://www.nature.com/nature/journal/v486/n7404/full/nature11124.html}, author = {S.E. Pierce and J.A. Clack and J.R, Hutchinson} }