@article{Tucker1999,
author = {Tucker, J.S. and Schwartz, J.E. and Clark, K.M. and Friedman, H.S.},
title= {Age-related changes in the associations of social network ties with mortality risk},
year = {1999},
doi = {10.1037/0882-7974.14.4.564},
journal = {Psychol Aging},
volume = {14},
number = {4},
pages = {564−571},
}