Fontanarosa, Phil B., and Stacy Christiansen. "Expressing Unit Names and Symbols." AMA Manual of Style. 20090401. Oxford University Press. Date of access 18 Jun. 2013, <http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-189>.
Fontanarosa, P., & Christiansen, S. (20090401). Expressing Unit Names and Symbols. AMA Manual of Style. Retrieved 18 Jun. 2013, from http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-189.
Fontanarosa, Phil B., and Stacy Christiansen. "Expressing Unit Names and Symbols." AMA Manual of Style. 18 Jun. 2013. http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-189.
Fontanarosa PB, Christiansen S. Expressing unit names and symbols. In: AMA Manual of Style: A Guide for Authors and Editors. New York, NY: Oxford University Press; 2007. http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-189. Accessed June 18, 2013.