Phanikumar CV, Maitra B. Modeling willingness-to-pay values for rural bus attributes under different trip purposes. JTRF. 2006;45(2):31-44. doi: 10.22004/ag.econ.206787
Renck-Hooper U, McKenna SP, Whalley D. Measuring quality of life in female urinary urge incontinence: development and psychometric properties of the IQoLI. J Drug Assess. 1998;1:41-8.