(2000). Preprimary Enrollment Rates. U.S. Department of Education.
Chicago-referens (17:e uppl.)Preprimary Enrollment Rates. U.S. Department of Education, 2000.
MLA-referens (9:e uppl.)Preprimary Enrollment Rates. U.S. Department of Education, 2000.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.