APA (7th ed.) Citation

De Bono, E. (1999). Six thinking hats (Rev. and updated ed.). Back Bay Books.

Chicago Style (17th ed.) Citation

De Bono, Edward. Six Thinking Hats. Rev. and updated ed. Boston: Back Bay Books, 1999.

MLA (9th ed.) Citation

De Bono, Edward. Six Thinking Hats. Rev. and updated ed. Back Bay Books, 1999.