APA (7th ed.) Zitazioa

Percentage Distribution of 6- to 12-year-olds, 1972-97. US Department of Education.

Chicago Style (17th ed.) Zitazioa

Percentage Distribution of 6- to 12-year-olds, 1972-97. US Department of Education.

MLA (9th ed.) Zitazioa

Percentage Distribution of 6- to 12-year-olds, 1972-97. US Department of Education.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.