@article{rockstrom2009a,
  title = {A safe operating space for humanity}
  author = {Rockström, Johan and Steffen, Will and Noone, Kevin and Persson, Asa and Chapin III, Stuart and Lambin, Eric F. and Lenton, Timothy M. and Scheffer, Marten and Folke, Carl and Schellnhuber, Hans Joachim and Nykvist, Björn and de Wit, Cynthia A. and Hughes, Terry and van der Leeuw, Sander and Rodhe, Henning and Sörlin, Sverker and Snyder, Peter K. and Costanza, Robert and Svedin, Uno and Falkenmark, Malin and Karlberg, Louise and Corell, Robert W. and Fabry, Victoria J. and Hansen, James and Walker Brian, },
  journal = {Nature},
  year = {2009}
}