Griessenauer, Christoph J.; Tubbs, R. Shane; Shoja, Mohammadali M.; Raborn, Joel; Boes, Christopher J. Journal of Neurosurgery: Spine, 19, 6, 12-2013, pàg. 750–758. DOI: 10.3171/2013.9.SPINE13220. PMID: 24138061 [Consulta: 23 abril 2016].
Griessenauer, Christoph J.; Tubbs, R. Shane; Shoja, Mohammadali M.; Raborn, Joel; Boes, Christopher J. Journal of Neurosurgery: Spine, 19, 6, 12-2013, pàg. 750–758. DOI: 10.3171/2013.9.SPINE13220. PMID: 24138061 [Consulta: 23 abril 2016].