Friend, G. (2004). Guide to business planning.
Lua i Stíl Chicago (17ú heag.)Friend, Graham. Guide to Business Planning. London, 2004.
Lua MLA (9ú heag.)Friend, Graham. Guide to Business Planning. 2004.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.