Herring WL, Herrmann JW. The single-day surgery scheduling problem: sequential decision-making and threshold-based heuristics. OR spectrum: quantitative approaches in management. 2012 Apr 1;34(2):429-59.
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.