To cite supplementary material from a journal article, treat it as part of the original source and include the specific supplementary file in your citation, typically by adding a descriptor after the article title or in parentheses at the end.
Basic Citation Format
Most citation styles follow this pattern: cite the main article first, then specify which supplementary material you're referencing. For example, in APA style, you would write the standard article citation and add "(Supplementary Material)" or the specific file name like "(Table S1)" after the title or at the end of the citation.
APA Example:
Smith, J., & Lee, K. (2023). Climate change impacts on coastal ecosystems. Journal of Marine Biology, 45(3), 112–130. https://doi.org/10.xxxx (Supplementary Table S2)
MLA Example:
Smith, John, and Karen Lee. "Climate Change Impacts on Coastal Ecosystems." Journal of Marine Biology, vol. 45, no. 3, 2023, pp. 112–130, supplementary material.
In-Text Citations
When referencing supplementary material in your text, specify which supplement you're citing: "According to the extended dataset (Smith & Lee, 2023, Supplementary Data 1)..." This helps readers locate the exact material you're discussing.
Accessing and Verifying Supplementary Files
Supplementary materials are usually hosted on the journal's website alongside the main article. Always verify the file name and type (e.g., "Supplementary Figure 3" vs. "Appendix A") as journals use different naming conventions. WisPaper's TrueCite automatically verifies citation formatting across styles and can help ensure your supplementary material citations follow the correct format for your target journal or institution.
Special Considerations
If the supplementary material has a separate DOI, include that instead of the article's main DOI. Some disciplines, particularly in the life sciences, treat large datasets or code repositories as separate citable objects—check your field's conventions. When supplementary material is extensive or independently valuable, consider whether it deserves a separate citation as a dataset or software package rather than as supplementary material.
