APA (7th ed.) Citation

Benedicto XVI & Ratzinger, J. (2009). Orar (1a. ed.). Planeta.

Chicago Style (17th ed.) Citation

Benedicto XVI and Joseph Ratzinger. Orar. 1a. ed. Santiago: Planeta, 2009.

MLA (9th ed.) Citation

Benedicto XVI and Joseph Ratzinger. Orar. 1a. ed. Planeta, 2009.