APA (7e ed.) Bronvermelding

Pennington, M. B. (1990). Call to the center: The Gospel's invitation to deeper prayer. Image Books.

Chicago (17e ed.) Bronvermelding

Pennington, M. Basil. Call to the Center: The Gospel's Invitation to Deeper Prayer. New York: Image Books, 1990.

MLA (9e ed.) Bronvermelding

Pennington, M. Basil. Call to the Center: The Gospel's Invitation to Deeper Prayer. Image Books, 1990.