Lua APA (7ú heag.)

(1866). Positivism.

Lua i Stíl Chicago (17ú heag.)

Positivism. 1866.

Lua MLA (9ú heag.)

Positivism. 1866.

Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.