Davies, D. C. (1887). A treatise on slate and slate quarrying. Crosby Locwood.
Lua i Stíl Chicago (17ú heag.)Davies, D. C. A Treatise on Slate and Slate Quarrying. London: Crosby Locwood, 1887.
Lua MLA (9ú heag.)Davies, D. C. A Treatise on Slate and Slate Quarrying. Crosby Locwood, 1887.
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