@article{Lawson2009,
author = {Lawson, D.W. and Mace, R.},
title= {Trade-offs in modern parenting: A longitudinal study of sibling competition for parental care},
year = {2009},
doi = {10.1016/j.evolhumbehav.2008.12.001},
volume = {30},
number = {3},
pages = {170--183},
}