00282nam a2200109Ia 4500008004000000082001300040100003900053245001900092260004300111300000800154650001000162210210b1968   xxu||||| |||| 00| 0 eng d  a535 VANW  aVAN HEEL (A C S) & VELZEL (C H F).  aWhat is light?  aLondonbWorld University Libraryc1968  a256  aLight