Respiratory Evolution Facilitated the Origin of Pterosaur Flight and Aerial Gigantism Claessens, Leon P. A. M. ; O'Connor, Patrick M. ; Unwin, David M. Abstract Publication: PLoS ONE Pub Date: February 2009 DOI: 10.1371/journal.pone.0004497 Bibcode: 2009PLoSO...4.4497C