Karl, C. A. (1990). Teacher observation in selected secondary schools of the Archdiocese of Chicago.
Lua i Stíl Chicago (17ú heag.)Karl, Catherine A. Teacher Observation in Selected Secondary Schools of the Archdiocese of Chicago. 1990.
Lua MLA (8ú heag.)Karl, Catherine A. Teacher Observation in Selected Secondary Schools of the Archdiocese of Chicago. 1990.
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