000 00294nam a2200121Ia 4500
008 190711s9999 xx 000 0 und d
082 _a541.3723 H474
100 _aHELFFERICH FRIEDRICH
245 0 _aION EXCHANGE
260 _aNEW YORK
_bMcGraw-Hill
_c1962
300 _a23X15
942 _cBK
_2DDC
999 _c12977
_d12977