(2000). Preprimary Enrollment Rates. U.S. Department of Education.
Cita Chicago (17th ed.)Preprimary Enrollment Rates. U.S. Department of Education, 2000.
Cita MLA (9th ed.)Preprimary Enrollment Rates. U.S. Department of Education, 2000.
Atenció: Aquestes cites poden no estar 100% correctes.