@article{Zettel2004,
author = {Zettel, L.A. and K.S., Rook},
title= {Substitution and compensation in the social networksof older widowed women},
year = {2004},
doi = {10.1037/0882-7974.19.3.433},
journal = {Psychology and Aging},
volume = {19},
number = {3},
pages = {433--443},
}