Walker, G. (2003). Modern competitive strategy. McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)Walker, Gordon. Modern Competitive Strategy. McGraw-Hill, 2003.
Lua MLA (8ú heag.)Walker, Gordon. Modern Competitive Strategy. McGraw-Hill, 2003.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.