1. S. Snowdon, “Teaching Geography to Visually Impaired Students,” QLS Staffordshire County Council, http://www.sln.org.uk /geography/segs01.htm [Accessed September 2, 2016]
2. B. L. McGinnity, J. Seymour-Ford, and K. J. Andries, “Geography,” Perkins History Museum, Perkins School for the Blind, http://www.perkins.org/history/curriculum/geography [Accessed September 2, 2016]
3. Räthgloben, 1917 Verlags GmbH, Relief-Leuchtglobus FRI 30 15, http://www.raethgloben.de/kollektionen/raethgloben-leipzig/relief-leuchtglobus-fri-30-15 [Accessed September 2, 2016]
4. Sun Kougei Co. Ltd., Barrier-free globe, http://www.sunkogei.co.jp /history/ [Accessed September 2, 2016]
5. Educational Insights Co. Ltd., GeoSafari Talking Globe, https: //www.educationalinsights.com/ [Accessed September 2, 2016]