Phanikumar CV, Maitra B. Willingness-to-pay and preference heterogeneity for rural bus attributes. J Transp Eng A-Syst. 2007 Jan;133(1).
Williams VSL, Jones LV, Tukey JW. Controlling error in multiple comparisons, with examples from state-to-state differences in educational achievement. J Educ Behav Stat. 1999;24(1):42-69. doi: 10.3102/10769986024001042