@article{Nagin2001,
author = {Nagin, D.S. and Tremblay, R.E.},
title= {Analyzing developmental trajectories of distinct but related behaviors: A group-based method},
year = {2001},
doi = {10.1037/1082-989X.6.1.18},
journal = {Psychological Methods},
volume = {6},
number = {1},
pages = {18--34},
}