MARSHALL, P. (1970). Biology Advanced Level Pt. Marshall. MacDonald & Evans.
Lua i Stíl Chicago (17ú heag.)MARSHALL, PT. Biology Advanced Level Pt. Marshall. MacDonald & Evans, 1970.
Lua MLA (8ú heag.)MARSHALL, PT. Biology Advanced Level Pt. Marshall. MacDonald & Evans, 1970.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.