(2000). Percentage of Higher Education Institutions Offering Distance Ed Courses. U.S. Department of Education.
Chicago Style (17. basım) AtıfPercentage of Higher Education Institutions Offering Distance Ed Courses. U.S. Department of Education, 2000.
MLA (9th ed.) AtıfPercentage of Higher Education Institutions Offering Distance Ed Courses. U.S. Department of Education, 2000.
Uyarı: Bu alıntı herzaman %100 doğru olmayabilir..