Robbins, L. (1952). An essay on the nature & significance of eco.sc (2nd rev.). Macmillan.
Lua i Stíl Chicago (17ú heag.)Robbins, Liohel. An Essay on the Nature & Significance of Eco.sc. 2nd rev. London: Macmillan, 1952.
Lua MLA (9ú heag.)Robbins, Liohel. An Essay on the Nature & Significance of Eco.sc. 2nd rev. Macmillan, 1952.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.