00300nam a2200109Ia 4500008004100000020001800041082001500059100001500074245004700089260004600136300000800182190710s9999    xx            000 0 und d  a81-313-0362-7  a371.3078 S  aSingh, Y K 0aEducational technology : teaching learning  aNew DelhibA P H Publihing Corporatc2009  a332