RT Article T1 Much ado about siblings: change models, sibship size, and intellectual development JF American sociological review VO 64 IS 2 SP 193 OP 198 A2 Downey, Douglas B. A2 Powell, Brian A2 Steelman, Lala Carr A2 Pribesh, Shana LA English YR 1999 UL https://krimdok.uni-tuebingen.de/Record/1639755225 K1 Intelligenzentwicklung K1 Geschwisteranzahl