Gaya APA

S., P, D. (1989). Letters 1-30. Transl. by Owen J. Blum. . Washington: Washington Catholic University of America Press.

Gaya MLA

S., Petrus, Damianus,. "Letters 1-30. Transl. by Owen J. Blum. ". Washington: Washington Catholic University of America Press, 1989. Buku.