Jackie Gaff. (2005). I Wonder Why Pine Trees Have Needles: And Other Questions About Forests. Gardners Books.
Lua i Stíl Chicago (17ú heag.)Jackie Gaff. I Wonder Why Pine Trees Have Needles: And Other Questions About Forests. Gardners Books, 2005.
Lua MLA (9ú heag.)Jackie Gaff. I Wonder Why Pine Trees Have Needles: And Other Questions About Forests. Gardners Books, 2005.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.