00333nam a2200157Ia 4500008004100000020000900041035001000050082001300060100001700073245002400090250000600114260003200120300000800152500000900160650000600169210723s9999||||xx |||||||||||||| ||und||  aNULL  a25188  a535BSIN  aSingh Harnam 0aPrniciples Of Light  a-  aN. DelhibChandan Prakashan  a287  a3791  a-