Cita APA (7a ed.)

Guitton, G., & Vannutelli, V. (1927). Léon Harmel, 1829-1915. Spes.

Cita Chicago Style (17a ed.)

Guitton, Georges, y Vincenzo Vannutelli. Léon Harmel, 1829-1915. Paris: Spes, 1927.

Cita MLA (9a ed.)

Guitton, Georges, y Vincenzo Vannutelli. Léon Harmel, 1829-1915. Spes, 1927.