Scharff, R. F. (1892). Perforations in carboniferous limestone.
Lua i Stíl Chicago (17ú heag.)Scharff, R. F. Perforations in Carboniferous Limestone. 1892.
Lua MLA (9ú heag.)Scharff, R. F. Perforations in Carboniferous Limestone. 1892.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.
