@article{Katz1983,
author = {Katz, S. and Branch, L.G. and Branson, M.H. and Papsidero, J.A. and Beck, J.C. and Greer, D.S.},
title= {Active life expectancy},
year = {1983},
journal = {New England Journal of Medicine},
volume = {309},
number = {20},
pages = {1218--1224},
}