Freiberg, K. (2004). Guts: Companies that blow the doors off business as usual. Currency.
Chicago-referens (17:e uppl.)Freiberg, Kevin. Guts: Companies That Blow the Doors off Business as Usual. New york: Currency, 2004.
MLA-referens (9:e uppl.)Freiberg, Kevin. Guts: Companies That Blow the Doors off Business as Usual. Currency, 2004.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.