Bahl R, Sinha A, Poulos C, Whittington D, Sazawal S, Kumar R, Mahalanabis D, Acosta CJ, Clemens JD, Bhan MK. Costs of illness due to typhoid fever in an Indian urban slum community: implications for vaccination policy. J Health Popul Nutr. 2004 Jan 1;22(3):304-10.