McKay, D. (1891). Critical philosophy.
Lua i Stíl Chicago (17ú heag.)McKay, Donald. Critical Philosophy. [N.p, 1891.
Lua MLA (8ú heag.)McKay, Donald. Critical Philosophy. 1891.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.