อ้างอิง ของ แผนที่รูปทีและโอ

  1. Isidore of Seville (c. 630). "14". Etymologiae (in ละติน).
  2. Stevens, Wesley M. (1980). "The Figure of the Earth in Isidore's 'De natura rerum'". Isis. 71 (2): 268–277. doi:10.1086/352464. JSTOR 230175.
  3. 1 2 Michael Livingston, Modern Medieval Map Myths: The Flat World, Ancient Sea-Kings, and Dragons Archived 2006-02-09 at the Wayback Machine., 2002.
  4. Hiatt, Alfred (2002). "Blank Spaces on the Earth". The Yale Journal of Criticism. 15 (2): 223–250. doi:10.1353/yale.2002.0019.