Regier DA, Sicsic J, Watson V. Choice certainty and deliberative thinking in discrete choice experiments. A theoretical and empirical investigation. J Econ Behav Organ. 2019 Aug;164:235-55. doi: 10.1016/j.jebo.2019.05.031
Phanikumar CV, Maitra B. Willingness-to-pay and preference heterogeneity for rural bus attributes. J Transp Eng A-Syst. 2007 Jan;133(1).