AMA @ Sullivan University: In-Text Citations

If you borrow information (even if you change the wording), you must document it. Any specific information that you use (other than common knowledge items), must be documented both in the paper (an an in-text citation) and on the reference page. 

In-Text Citations

• Use superscript numbers outside periods and commas, inside colons and semicolons.
• When more than two references are cited at a given place, use hyphens to join the first and last numbers of a closed series or use commas without spaces to separate other parts.
• Number references in the order they appear in your paper
• Using author names is optional in the text of your paper

Examples

• As reported previously,^1,3-8,19
• The derived data were as follows^3,4::
• "Some classes of drugs show more promise than others. Gradishar evaluated taxanes as a class."¹¹ 
• Yang et al.⁷ reviewed...

For more information see APA Manual of Style 11th edition, section 3.6.