Vass C, Gray E, Payne K. Discrete choice experiments of pharmacy services: a systematic review. Int J Clin Phar. 2016 Jun;38(3):620-30. doi: 10.1007/s11096-015-0221-1
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.