Lurie, Stephen J. "Spacing With Mathematical Symbols." AMA Manual of Style. 20090401. Oxford University Press. Date of access 23 May. 2013, <http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-230>.
Lurie, S. (20090401). Spacing With Mathematical Symbols. AMA Manual of Style. Retrieved 23 May. 2013, from http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-230.
Lurie, Stephen J. "Spacing With Mathematical Symbols." AMA Manual of Style. 23 May. 2013. http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-230.
Lurie SJ. Spacing with mathematical symbols. In: AMA Manual of Style Committee. AMA Manual of Style: A Guide for Authors and Editors. 10th ed. New York, NY: Oxford University Press; 2007. http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-230. Accessed May 23, 2013.