Heptagon

Bu kavram başka kaynaklarda da geçiyor

• The American Dictionary and Cyclopedia (1910)
• Chamber's Twientieth Century Dictionary (1908)
• The Optical Dictionary (1904)
• Chamber's Etymological of the English Language (1895)
• An Illustrated Encyclopedic Medical Dictionary (1893)
• An Illustrated Dictionary of Words Used In Art and Archealogy. (1883)
• Zell's Condensed Dictionary (1879)
• Dictionary of Science, Literature and Art (1854)
• Dictionary of Science, Literature and Art (1842)
• A Military Dictionary (1810)