000 00300nam a2200109Ia 4500
008 220421s1969 xx 000 0 und d
041 _aeng
082 _a507
_bRIC/SCI
100 _aRichardson ,John S.
_9569836
245 _aScience teaching in secondary school
260 _aN.Delhi
_b N.C.E.R.T.
_c1969
999 _c395936
_d395936