000 00267nam a2200109Ia 4500
008 240421s9999 xx 000 0 und d
100 _aAggarwal, D.D.
245 0 _aEducational Technology
260 _aNew Delhi
_bSarup and Sons
_c2008
300 _a280p.
942 _cBK
999 _c13775
_d13775