APA (7th ed.) Citation

Porter, D., & Prince, D. (2008). Frommer's Portugal (20th ed.). Wiley.

Chicago Style (17th ed.) Citation

Porter, Darwin, and Danforth Prince. Frommer's Portugal. 20th ed. Hoboken, N.J: Wiley, 2008.

MLA (9th ed.) Citation

Porter, Darwin, and Danforth Prince. Frommer's Portugal. 20th ed. Wiley, 2008.