(2007). Changes in Instructional Hours in Four Subjects by Public School Teachers of Grades 1 Through 4. U.S. Department of Education.
Chicago Style aipamenaChanges in Instructional Hours in Four Subjects by Public School Teachers of Grades 1 Through 4. U.S. Department of Education, 2007.
MLA aipamenaChanges in Instructional Hours in Four Subjects by Public School Teachers of Grades 1 Through 4. U.S. Department of Education, 2007.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.