P. Goldstein et al., “Brain-to-Brain Coupling during Handholding Is Associated with Pain Reduction,” Proceedings of the National Academy of Sciences 115, no. 11 (March 13, 2018): E2528– E2537, doi: 10.1073/pnas.1703643115; University of Colorado at Boulder, “Holding Hands Can Sync Brainwaves, Ease Pain, Study Shows,” ScienceDaily, March 1, 2018, https://www.sciencedaily.com/releases /2018/03/180301094822.htm.
