@article{Geurts2009,
author = "Geurts, T. and Poortman, A. R. and Van Tilburg, T.G. and Dykstra, P.",
title = "Contact between grandchildren and theirs grandparents in early adulthood",
year = 2009,
journal = "Journal of Family Issues",
volume = 30(12),
pages = "1698-1713"
}