Phanikumar CV, Maitra B. Willingness-to-pay and preference heterogeneity for rural bus attributes. J Transp Eng A-Syst. 2007 Jan;133(1).
Holmes SJ, McKenna SP, Doward LC, Hunt SM, Shalet SM. Development of a questionnaire to assess the quality of life of adults with growth hormone deficiency. Endocrinology and metabolism. 1995 Jan 1;2(1):63-9.
Agha M, Gnanasakthy A. A cluster analysis of the effects of storage mites as allergens in relation to certain occupations and living conditions. Clin Allergy. 1981 Sep;11(5):499-504.