Dyfyniad APA

(2000). Trends in Science Performance of 9-, 13-, & 17-year olds. U.S. Department of Education.

Dyfyniad Arddull Chicago

Trends in Science Performance of 9-, 13-, & 17-year Olds. U.S. Department of Education, 2000.

Dyfyniad MLA

Trends in Science Performance of 9-, 13-, & 17-year Olds. U.S. Department of Education, 2000.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.