Babbitt, H. E. Sewerage and Sewage Treatment.
Lua i Stíl Chicago (17ú heag.)Babbitt, Harold E. Sewerage and Sewage Treatment.
Lua MLA (9ú heag.)Babbitt, Harold E. Sewerage and Sewage Treatment.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.