Wion RK, Hill NL, Mogle J, Bhargava S, Berish D, Kolanowski A. Scoring of leisure activities for older adults according to cognitive, physical, and social components. Res Gerontol Nurs. 2020 Jan 1;13(1):13-20. doi: 10.3928/19404921-20191022-01
Wardman M, Chintakayala PK, de Jong G. Values of travel time in Europe: review and meta-analysis. Transp Res Part A Policy Pract. 2016 Dec;94:93-111. doi: 10.1016/j.tra.2016.08.019