C. Heber D. (Februar 1911). »Methods of Silvering Mirrors«. Publications of the Astronomical Society of the Pacific. Zv. 23, št. 135. str. 15–19. Bibcode:1911PASP...23...13C. doi:10.1086/122040.
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C. Heber D. (Februar 1911). »Methods of Silvering Mirrors«. Publications of the Astronomical Society of the Pacific. Zv. 23, št. 135. str. 15–19. Bibcode:1911PASP...23...13C. doi:10.1086/122040.