@article{Bradburn2003,
author = {Bradburn, M.J. and Clark, T.G. and Love, S.B. and Altman, D.G.},
title= {Survival analysis part II: Multivariate data analysis: An introduction to concepts and methods},
year = {2003},
doi = {10.1038/sj.bjc.6601119},
volume = {89},
number = {3},
pages = {431--436},
}