RT Article T1 Initiation patterns and trends of e-cigarette and cigarette use among U.S. adolescents JF Journal of adolescent health VO 66 IS 1 SP 27 OP 33 A1 Evans-Polce, Rebecca J. A1 McCabe, Sean Esteban A1 Boyd, Carol J. A1 Veliz, Philip A2 McCabe, Sean Esteban A2 Boyd, Carol J. A2 Veliz, Philip LA English YR 2020 UL https://krimdok.uni-tuebingen.de/Record/1912592088 DO 10.1016/j.jadohealth.2019.07.002