@article{Shepard1980,
author = {Shepard, D.S. and Zeckhauser, R.J.},
title= {Long-term effects of interventions to improve survival in mixed populations},
year = {1980},
doi = {10.1016/0021-9681(80)90039-9},
journal = {Journal of Chronic Diseases},
volume = {33},
number = {7},
pages = {413--433},
}