Davidson, G. (2014). North American tunneling: 2014 proceedings. Society for Mining Metallurgy and Exploration.
Lua i Stíl Chicago (17ú heag.)Davidson, Gregg. North American Tunneling: 2014 Proceedings. Colorado: Society for Mining Metallurgy and Exploration, 2014.
Lua MLA (9ú heag.)Davidson, Gregg. North American Tunneling: 2014 Proceedings. Society for Mining Metallurgy and Exploration, 2014.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.