000 00263nam a2200121Ia 4500
001 2620
008 231023s9999 xx 000 0 und d
100 1 _aPiaget, Jean
245 1 0 _aEstudios sociológicos
260 _aAriel 1977,
_c1977
999 _c44268
_d44268
942 _n1
942 _n1