↑ http://www.sabai.com/patience/bububu.htm ↑ "Archived copy". Archived from the original on 2010-01-26. Retrieved 2016-10-19. ↑ http://www.dspace.cam.ac.uk/handle/1810/781 ↑ http://www.swahilicoast.com/contents.php?bbb=42&cc=3