One Europe, many nations: a historical dictionary of European national groups, James Minahan, Greenwood Publishing Group, 2000, ISBN 0-313-30984-1, pp. 134 – 135. Google Books. Teoksen verkkoversio Viitattu 13.11.2011.
Bulgaria Yhdysvalloissa. Joshuaproject.net. Joshua Project is a research initiative seeking to highlight the ethnic people groups of the world with the fewest followers of Christ. Accurate, updated ethnic people group information is critical for understanding and completing the Great Commission. Revelation 5:9 and 7:9-10 show that there will be some from every tribe, tongue, nation and people before the Throne. Viitattu 3.7.2018.
