Não informado. (1974). Coal and Energy Quarterly. National Coal Board.
Lua i Stíl Chicago (17ú heag.)Não informado. Coal and Energy Quarterly. London: National Coal Board, 1974.
Lua MLA (8ú heag.)Não informado. Coal and Energy Quarterly. National Coal Board, 1974.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.