RT Article T1 Advances in group-based trajectory modeling and an SAS procedure for estimating them JF Sociological methods and research VO 35 IS 4 SP 542 OP 571 A1 Jones, Bobby L. A2 Nagin, Daniel 1948- LA English YR 2007 UL https://krimdok.uni-tuebingen.de/Record/1912451492 DO 10.1177/0049124106292364