00381nam a2200169Ia 4500003000400000005001700004008004100021040000700062041000800069082001600077100002100093245003600114260001900150300000900169650001400178700001900192OSt20251209123725.0250729s1944 xx 000 0 und d cAL aeng a370.15 BURG aBurton H WilliAM aGuidance of learning activities aNew Yorkc1944 a737p aEducation aRao Digumurthi