@article{Danielsbacka2011,
author = {Danielsbacka, M. and Tanskanen, A.O. and Jokela, M. and Rotkirch, A.},
title= {Grandparental child care in Europe: Evidence for preferential investment in more certain kin},
year = {2011},
journal = {Evolutionary Psychology },
volume = {9},
number = {1},
pages = {3--24},
}