@article{Klein Ikkink1999,
author = {Klein Ikkink, K. and van Tilburg, T. and Knipscheer, K.C.P.M.},
title= {Perceived instrumental support exchanges in relationships between elderly parents and their adult children: normative and structural explanations},
year = {1999},
doi = {10.2307/354006},
journal = {Journal of Marriage and the Family},
volume = {61},
number = {4},
pages = {831--844},
}