Traulsen, Arne; Hauert, Christoph; De Silva, Hannelore; Nowak, Martin A.; Sigmund, Karl(Proceedings of the National Academy of Sciences of the United States of America, 2009)Link to Published Version
Squyres, Steven W.; Knoll, Andrew Herbert; Arvidson, Raymond E.; Ashley, James W.; Bell, James F. III; Calvin, Wendy M.; Christensen, Philip R. et al.(Science, 2009)Link to Published Version