Singer, I. (1957). Santayana's aesthetics: A critical introduction. Harvard University Press.
Lua i Stíl Chicago (17ú heag.)Singer, Irving. Santayana's Aesthetics: A Critical Introduction. Cambridge: Harvard University Press, 1957.
Lua MLA (9ú heag.)Singer, Irving. Santayana's Aesthetics: A Critical Introduction. Harvard University Press, 1957.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.