Smith, G. F. H. (1907). The Herbert Smith refractometer and its use: Particularly for the discrimination of faceted gem-stones. London: J. H. Steward.
Παραπομπή Chicago StyleSmith, George Frederick Herbert. The Herbert Smith Refractometer and Its Use: Particularly for the Discrimination of Faceted Gem-stones. London: J. H. Steward, 1907.
Παραπομπή MLASmith, George Frederick Herbert. The Herbert Smith Refractometer and Its Use: Particularly for the Discrimination of Faceted Gem-stones. London: J. H. Steward, 1907.
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