(2000). Percentage of Students Using Drugs During the Previous 30 Days: 1991-98. U.S. Department of Education.
Cita Chicago (17th ed.)Percentage of Students Using Drugs During the Previous 30 Days: 1991-98. U.S. Department of Education, 2000.
Cita MLA (9th ed.)Percentage of Students Using Drugs During the Previous 30 Days: 1991-98. U.S. Department of Education, 2000.
Atenció: Aquestes cites poden no estar 100% correctes.