Armstead, H. C. H. Geothermal enrgy reviewof research and development. UNESCO.
Lua i Stíl Chicago (17ú heag.)Armstead, H. Christopher H. Geothermal Enrgy Reviewof Research and Development. UNESCO.
Lua MLA (8ú heag.)Armstead, H. Christopher H. Geothermal Enrgy Reviewof Research and Development. UNESCO.
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