APA (7th ed.) Citation
Thielicke, H. (1968). I believe: The Christian's creed. Fortress Press.
Chicago Style (17th ed.) Citation
Thielicke, Helmut. I Believe: The Christian's Creed. Philadelphia: Fortress Press, 1968.
MLA (9th ed.) Citation
Thielicke, Helmut. I Believe: The Christian's Creed. Fortress Press, 1968.
Warning: These citations may not always be 100% accurate.