Harker J. H. & Backhurst J. R. (1981). Fuel and energy. London, Academic Press, 1981.
Lua i Stíl Chicago (17ú heag.)Harker J. H. agus Backhurst J. R. Fuel and Energy. London, Academic Press, 1981, 1981.
Lua MLA (9ú heag.)Harker J. H. agus Backhurst J. R. Fuel and Energy. London, Academic Press, 1981, 1981.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.