See:
- William Gell, The Itinerary of Greece. Containing One Hundred Routes in Attica, Bœtica, Phocis, Locris, and Thessaly, Rodwell and Martin 1819, pp. 201-203 - https://books.google.pl/books?id=9pZgAAAAcAAJ&pg=PA201&lpg=PA201&dq=panopea+ancient&source=bl&ots=ZvERz6VeLE&sig=vJi8yLxvR7w8vAJ4UgHMaKuFnLU&hl=pl&sa=X&ved=0ahUKEwjX7_WemebOAhVLG5oKHaEoBL0Q6AEIJjAD