00390nam a2200133Ia 450000500170000000800460001703700160006304000210007904100130010008400090011324500260012224500440014826000640019220250508162216.0008  250505s9999    xx            000 0 eng d  aPeriodicals  aFEDL bengcFEDL  aeng2eng  qFEDL 0aResearch in education 0cEducational Research Information Center  aWashington, USAbDepartment of Health Education and Welfare