000 00261nam a2200097Ia 4500
008 230421s9999 xx 000 0 eng d
100 _aTyagi (Onkar Singh) Gupta (Surya Dev)
245 0 _aVigyan Shikshan
260 _bArihant Shiksha Prakashan
942 _2ddc
_cBED
999 _c21695
_d21695