Phanikumar CV, Maitra B. Willingness-to-pay and preference heterogeneity for rural bus attributes. J Transp Eng A-Syst. 2007 Jan;133(1).
Strickland A, Brogan AJ, Krauss J, Martindale R, Cresci G. Is the use of specialized nutritional formulations a cost-effective strategy? A national database evaluation. J Parenter Enter Nutr. 2005 Jan 1;29(1 Suppl):S81-91.