Whittington D, Sur D, Cook J, Chatterjee S, Maskery B, Lahiri M, Poulos C, Boral S, Nyamete A, Deen J, Ochiai L, Bhattacharya SK. Rethinking cholera and typhoid vaccination policies for the poor: private demand in Kolkata, India. World Dev. 2009 Feb 1;37(2):399-409.
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.