Claude, R. (1960). The soul of Pier-Giorgio Frassati. Spiritual Book Association.
Lua i Stíl Chicago (17ú heag.)Claude, Robert. The Soul of Pier-Giorgio Frassati. New York: Spiritual Book Association, 1960.
Lua MLA (8ú heag.)Claude, Robert. The Soul of Pier-Giorgio Frassati. Spiritual Book Association, 1960.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.