1. Thorsson, pp. 637–638.

2. Ibid., pp. 638–641.

3. Ibid., p. 639.

4. Ibid., pp. 644–645.

5. Ibid., p. 647.

6. Ibid., pp. 648, 670; Helge Ingstad and Anne Stine Ingstad, The Viking Discovery of America (2001), p. 48.

7. Alice Beck Kehoe, America Before the European Invasions (2002), p. 1.

8. Stuart J. Fiedel, Prehistory of the Americas (1987), pp. 152–153, 156–157; Kehoe, p. 102.

9. Fiedel, pp. 237, 254–257; Kehoe, pp. 175–177.

10. Kehoe, pp. 148–150; Fiedel, pp. 214–217.

11. Adams, p. 63.

12. Ibid., pp. 63–65.

13. Hans J. Prem, The Ancient Americas (1997), pp. 18–19; Robert J. Sharer and Sylvanus Griswold Morley, The Ancient Maya, 5th ed. (1994), pp. 471–472; Nicholas J. Saunders, Ancient Americas (2004), p. 84.

14. Adams, p. 79; Saunders, Ancient Americas, p. 48.

15. H. B. Nicholson, Topiltzin Quetzalcoatl (2001), pp. 250–251.

16. Prem, pp. 21–22; Adams, pp. 68–69; Saunders, Ancient Americas, p. 79.

17. Nicholson, pp. 10–11.

18. Prem, p. 24; Adams, p. 73.

19. Adams, p. 75.