000 00287nam a2200121Ia 4500
003 LDD
040 _cLDD
041 _aen
245 0 _aCommunications of the ACM
260 _aAssociation for Computing Machinery
_bNewyork
_c1 Jan-30 Apr,1990
362 _a33-33
_b01-Apr
942 _2ddc
_cJ
999 _c189581
_d189581