Piper, O. A. (1965). Protestantism in an ecumenical age: Its root, its right, its task. Fortress.
Chicago Style (17th ed.) CitationPiper, Otto A. Protestantism in an Ecumenical Age: Its Root, Its Right, Its Task. Philadelphia: Fortress, 1965.
MLA (9th ed.) CitationPiper, Otto A. Protestantism in an Ecumenical Age: Its Root, Its Right, Its Task. Fortress, 1965.
Warning: These citations may not always be 100% accurate.
