00421nam a2200133Ia 4500008004100000040001700041082002400058100002900082245004600111250000800157260003200165300001600197650007400213190328s9999||||xx |||||||||||||| ||und||  aNITILcNITIL  221sta370.15bS628E  aSkinner, Charles E (Ed.) 0aEducational psychologycCharles E Skinner  a3rd  aLondonbStaples Pressc1952  aviii, 791p.  aEduactional psychology; Ability grouping in education; Human behavior