@article{Pickles1995,
author = {Pickles, A. and Crouchley, R.},
title= {A comparison of frailty models for multivariate survival data},
year = {1995},
doi = {10.1002/sim.4780141305},
journal = {Statistics in Medicine},
volume = {14},
number = {13},
pages = {1447--1461},
}