Twelve encyclicals

MLA

Pius, and Philip Edward Hallett. Twelve Encyclicals. London: Catholic truth society, 1943.

APA

Pius, P., & Hallett, P. Edward. (1943). Twelve encyclicals. London: Catholic truth society.

Chicago

Pius, and Philip Edward Hallett. Twelve Encyclicals. London: Catholic truth society, 1943.