Opera-glass Stereoscope

Bu kavram başka kaynaklarda da geçiyor

• OPERA — The Devil's Dictionary (1911)
• Opera — Webster's Condensed Dictionary- A Condensed Dictionary of the English Language (1909)
• Opera — Chamber's Twientieth Century Dictionary (1908)
• Opera — Nuttall Encyclopedia (1907)
• OPERA — Foolish Dictionary (1904)
• Opera — Encyclopedic Dictionary of American Reference (1901)
• OPERA — Pears Shilling Cyclopedia (1898)
• Opera — Webster's Practical Dictionary- A Practical Dictionary of the Englih Language (1884)
• Opera — An Illustrated Dictionary of Words Used In Art and Archealogy. (1883)