6Zarzur E. Physiologic change of the cross-sectionalmeasurements of the spinal canal and interverbral foramina as a function of body position[J]. AJR,2000,174 : 1787 - 1788
7Higgins JPT,Green S. Cochrane Handbook for Systematic Reviews of Interventions Version 5.0. 1 [ updated February 2008 ] [ EB/ OL]. The Cochrane Collaboration, 2008. Available from www. cochrane-handbook, org.