000 00265nam a2200109Ia 4500
001 77311
008 170722s9999 xx 000 0 und d
245 _aLogic 2 :
_bProof unit 17 /
260 _bOpen University Press ,
_c1971.
300 _a56 p.
_c29cms
942 _cGEN
999 _c94978
_d94978