Gaya APA
Guardini, R. (1985).
The art of praying: The priciples and methods of Christian prayer. : Vorschule des Betens. .
Manchester:
Manchester Sophia Institute Press.
Gaya MLA
Guardini, Romano.
"The art of praying: The priciples and methods of Christian prayer. : Vorschule des Betens. ".
Manchester:
Manchester Sophia Institute Press,
1985.
Buku.