Ortman, Steve (trans.); Laqua, Charsten, "Carl Barks – the AuthorArchived June 12, 2007, at the Wayback Machine", Carl Barks His Work and His Life (site). Retrieved on September 5, 2007.
Ortman, Steve (trans.); Laqua, Charsten, "Carl Barks – the AuthorArchived June 12, 2007, at the Wayback Machine", Carl Barks His Work and His Life (site). Retrieved on September 5, 2007.