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
Cohen LM, Britt DM, Collins FL, Stott HD, Carter LC. Chewing gum affects smoking topography. Exp Clin Psychopharmacol. 1999 Nov 1;7(4):444-7.