Yopp JM, Deal AM, Nakamura ZM, Park EM, Edwards T, Wilson DR, Biesecker B, Rosenstein DL. Psychological and parental functioning of widowed fathers: the first two years. J Fam Psychol. 2019 Aug;33(5):565-74. doi: 10.1037/fam0000528
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