RT Article T1 A study of genetic and environmental effects on the co-occurrence of problem behaviors in three-year-old twins JF Journal of abnormal psychology VO 109 IS 3 SP 360 OP 372 A1 Van den Oord, Edwin J. C. G. A1 Boomsma, Dorret 1957- A1 Verhulst, Frank C. LA English YR 2000 UL https://krimdok.uni-tuebingen.de/Record/1639679324 K1 Verhaltensauffälligkeiten K1 Anlage-Umwelt K1 Kinder