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
Varadhachary GR, Karanth S, Qiao W, Carlson HR, Raber MN, Hainsworth JD, Greco FA. Carcinoma of unknown primary with gastrointestinal profile: immunohistochemistry and survival data for this favorable subset. Int J Clin Oncol. 2014;19(3):479-84. doi: 10.1007/s10147-013-0583-0