Indigo Copper

Bu kavram başka kaynaklarda da geçiyor

• indigo-copper — The Century Dictionary: The Encyelopedic Lexicon of the English Language (1887)
• Copper — A Dictionary of Scientific Terms (1927)
• COPPER — Adair's New Encyclopedia (1923)
• INDIGO — Adair's New Encyclopedia (1923)
• Indigo — French-English and English-French Commercial Dictionary (1918)
• Copper — French-English and English-French Commercial Dictionary (1918)
• COPPER — A Vocabulary of Criminal Slang (1915)
• Copper — Hawkins' Electrical Dictionary (1915)
• Copper — The Slang Dictionary Etymological Historical and Anecdotal (1913)
• copper — The American Illustrated Medical Dictionary (1913)
• Copper — Everybody's Encyelopedia (1912)
• INDIGO — The Grocer's Eneyclopedia (1911)
• Copper — Chamber's Twientieth Century Dictionary (1908)
• Indigo — Chamber's Twientieth Century Dictionary (1908)
• Indigo — A Dictionary of Men's Wear (1908)