Não informado. (2001). Bulletin of the Pennsylvania Geological Survey. Pennsylvania Geological Survey.
Lua i Stíl Chicago (17ú heag.)Não informado. Bulletin of the Pennsylvania Geological Survey. Harrisburg, Pa: Pennsylvania Geological Survey, 2001.
Lua MLA (8ú heag.)Não informado. Bulletin of the Pennsylvania Geological Survey. Pennsylvania Geological Survey, 2001.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.