Christiansen, Stacy. "Shift in Number of Subject and Resultant Subject-Verb Disagreement." AMA Manual of Style. 20090401. Oxford University Press. Date of access 21 May. 2013, <http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div2-285>.
Christiansen, S. (20090401). Shift in Number of Subject and Resultant Subject-Verb Disagreement. AMA Manual of Style. Retrieved 21 May. 2013, from http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div2-285.
Christiansen, Stacy. "Shift in Number of Subject and Resultant Subject-Verb Disagreement." AMA Manual of Style. 21 May. 2013. http://www.amamanualofstyle.com/view/10.1093/jama/9780195176339.001.0001/med-9780195176339-div2-285.
Christiansen S. Shift in number of subject and resultant subject-verb disagreement. 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-div2-285. Accessed May 21, 2013.