AMA requires the use of superscript Arabic numerals in consecutive order when citing references in-text.
The first in-text citation in your paper will be ¹. If you cite the same reference again, you will use the superscript ¹ again.
The superscript numbers will correlate with the reference list at the end of your paper.
Place superscripts outside of periods and commas, and inside colons and semicolons, directly following the statement or fact that you're referencing.
When citing two or more references in the same spot, use hyphens to connect the range of references cited in consecutive order. If the references that you're citing are not in consecutive order, use a comma to separate.
This is an example of how you would cite multiple references at the end of a sentence.1-3,5,8
Here's how a paper would look like with in-text citations and a reference list at the end of the document:
The opioid epidemic is a serious problem in the United States, responsible for over 700,000 deaths beginning in the 1990s with the rise of prescription opioids.1-2The most recent increases in opioid overdoses have been attributed to illicitly-manufactured fentanyl,1which can be found laced into substances such as heroin and cocaine.3
1. Understanding the epidemic. Centers for Disease Control and Prevention Web site. https://www.cdc.gov/drugoverdose/epidemic/index.html. Updated December 19, 2018. Accessed April 24, 2019.
2. Kolodny A, Courtwright DT, Hwang CS. The prescription opioid and heroin crisis: a public health approach to an epidemic of addiction.Annu Rev Public Health. 2015;36():559-574. doi: 10.1146/annurev-publhealth-031914-122957.
3. Rudd RA, Aleshire N, Zibbell JE, Gladden RM. Increases in drug and opioid overdose deaths--United States, 2000-2014.MMWR Morb Mortal Wkly Rep. 2016;64(50-51):1378-1382. doi: 10.15585/mmwr.mm6450a3.