000 00233nam a2200097Ia 4500
008 190719s9999 xx 000 0 und d
100 _aK R Choudhary/D P Gupta/O P Gupta
260 _aDelhi
_bR Chand
_c1972
650 _aMath
942 _cBK
999 _c1111
_d1111