Billings, J. S. (1893). Ventilation and heating. The Engineering record.
Lua i Stíl Chicago (17ú heag.)Billings, John S. Ventilation and Heating. New York: The Engineering record, 1893.
Lua MLA (8ú heag.)Billings, John S. Ventilation and Heating. The Engineering record, 1893.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.