Saigi N, Espelt A, Folch C, Sarasa-Renedo A, Castellano Y, Majo X, Merono M, Brugal MT, Casabona J, REDAN Group. Differences in illegal drug consumption between native and immigrants in a large sample of injected drug users in Catalonia (Spain). Adicciones. 2014;26(1):69-76. doi: 10.20882/adicciones.136
Cropper ML, Haile M, Lampietti J, Poulos C, Whittington D. The demand for a malaria vaccine: evidence from Ethiopia. J Dev Econ. 2004 Oct 1;75(1):303-18.