00305nam a2200109Ia 4500008004100000082001500041100001900056245006200075250000800137260004200145300000800187190709s9999    xx            000 0 und d  a371(1) R5P  aRisk, Thomas M 0aPrinciples and practices of teaching in secondary schools  a3rd  aNew YorkbAmerican Book Companyc1951  a526