Dyfyniad APA

 Thorpe, G. S. (2007).  AP environmental science.  Barron’s Educational Series.

Dyfyniad Arddull Chicago

 Thorpe, Gary S.  AP Environmental Science.  Barron’s Educational Series, 2007.

Dyfyniad MLA

 Thorpe, Gary S.  AP Environmental Science.  Barron’s Educational Series, 2007.

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