Киселев, А., and П. Кротенков. “Posttraumatic Axis Dens Pseudoarthrosis: Report of 12 Cases Managed via Modified Craniocervical Fusion and Anterior Screw Fixation”. Bulletin of the International Scientific Surgical Association, Vol. 2, no. 2-3, May 2007, pp. 27-31, http://surgjournal.ru/index.php/BISSA/article/view/193.