@article{Rondeau2003,
author = {Rondeau, V. and Commenges, D. and Joly, P.},
title= {Maximum Penalized Likelihood Estimation in a Gamma-Frailty Model},
year = {2003},
doi = {10.1023/a:1022978802021},
journal = {Lifetime Data Analysis},
volume = {9},
number = {2},
pages = {139--153},
}