Pierce, G. F. (2001). Spirituality @ workGregory F. A. Pierce. Kanisius.
Lua i Stíl Chicago (17ú heag.)Pierce, Gregory F.A. Spirituality @ WorkGregory F. A. Pierce. Kanisius, 2001.
Lua MLA (8ú heag.)Pierce, Gregory F.A. Spirituality @ WorkGregory F. A. Pierce. Kanisius, 2001.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.