Sobral, J. M. (1913). Contributions to the geology of the Nordingra region. Almquist & Wiksells boktryckeri.
Lua i Stíl Chicago (17ú heag.)Sobral, José M. Contributions to the Geology of the Nordingra Region. Uppsala: Almquist & Wiksells boktryckeri, 1913.
Lua MLA (8ú heag.)Sobral, José M. Contributions to the Geology of the Nordingra Region. Almquist & Wiksells boktryckeri, 1913.
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