1、Littlefield, C. H., & Rushton, J. P. (1986). When a child dies: The sociobiology of bereavement.Journal of Personality and Social Psychology, 51(4), 797–802. doi.org/10.1037/0022-3514.51.4.797 当孩子死去,亲属的伤心程度:外婆>外公≈祖母>祖父,母亲的兄弟姐妹>父亲的兄弟姐妹
2、Danielsbacka, M., Tanskanen, A. O., Jokela, M., & Rotkirch, A. (2011). Grandparental child care in Europe: Evidence for preferential investment in more certain kin. Evolutionary Psychology, 9(1), 3–24. doi.org/10.1177/147470491100900102 对照顾孩子的投入:外婆>外公>祖母>祖父
3、Pollet, T. V., Nettle, D., & Nelissen, M. (2007). Maternal grandmothers do go the extra mile: Factoring distance and lineage into differential contact with grandchildren. Evolutionary Psychology, 5(4), 832–843. doi.org/10.1177/147470490700500412 当祖孙之间距离较远时,前往看望孙辈的可能性:外婆>外公>祖母≈祖父