Grassian, V. (1984). Perennial philosophical issues. Prentice hall.
Lua i Stíl Chicago (17ú heag.)Grassian, Victor. Perennial Philosophical Issues. New Jersey: Prentice hall, 1984.
Lua MLA (9ú heag.)Grassian, Victor. Perennial Philosophical Issues. Prentice hall, 1984.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.