Fontanarosa, Phil B., and Stacy Christiansen. "Use of Numerals With Units." AMA Manual of Style. 20090401. Oxford University Press. Date of access 19 May. 2013, <http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-191>.
Fontanarosa, P., & Christiansen, S. (20090401). Use of Numerals With Units. AMA Manual of Style. Retrieved 19 May. 2013, from http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-191.
Fontanarosa, Phil B., and Stacy Christiansen. "Use of Numerals With Units." AMA Manual of Style. 19 May. 2013. http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-191.
Fontanarosa PB, Christiansen S. Use of numerals with units. In: AMA Manual of Style Committee. AMA Manual of Style: A Guide for Authors and Editors. 10th edition ed. New York, NY: Oxford University Press; 2007:792-794. http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div1-191. Accessed May 19, 2013.