00435nam a2200145Ia 4500008004100000020001500041041000800056082001700064100004200081245007600123260005400199300001500253365000700268650001400275210719s1984    xx            000 0 und d  a0534014593  aeng  a370.285 WALI  aWALKER (Decker F) and HESS (Robert D)  aInstructional software: principles and perspectives for design and use.  aCalifornia.bWadsworth Publishing Company.,c1984  axi,308bPB  cRs  aEducation