Fox, M., Sear, R., Beise, J., Ragsdale, G., Voland, E., & Knapp, L. (2010). Grandma plays favourites: X-chromosome relatedness and sex-specific childhood mortality. Proceedings of the Royal Society B: Biological Sciences, 277(1681), 567-573. https://doi.org/10.1098/rspb.2009.1660