(1980). Guidebook on biogas development.
Lua i Stíl Chicago (17ú heag.)Guidebook on Biogas Development. 1980.
Lua MLA (9ú heag.)Guidebook on Biogas Development. 1980.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.
Lua APA (7ú heag.)