Drivers of change in crop–livestock systems and their potential impacts on agro-ecosystems services and human wellbeing to 2030: A study commissioned by the CGIAR Systemwide Livestock Programme - Herrero, Mario; Thornton, Philip K.; Notenbaert, An Maria Omer; Msangi, Siwa; Wood, S.; Kruska, Russell L.; Dixon, John A.; Bossio, Deborah A.; Steeg, Jeannette van de; Freeman, H.A.; Li, X.; Parthasarathy Rao, P. (International Livestock Research Institute, 2012)