00293nam a22001097a 4500003000800000008004100008041001200049082001600061100002000077245004200097260004400139WUSLLib200910b           ||||| |||| 00| 0 eng d  aEnglish  a535.32bOPE  aOpen University  aPhysics :bgeometrical optics block 1  aNugegoda: bThe Open University, c1986