Most standards support searching additional sources after database searching is completed. Depending on the topic, one or all of the below methods may be appropriate. A librarian may be able to contribute to developing a plan.
- Grey Literature: Grey literature includes unpublished studies, reports, conference proceedings, and other materials from professional organizations or governmental agencies. Grey literature may be challenging to locate. Unpublished studies should be consulted to reduce the risk of publication bias in results. See the UI Libraries' Gray/Grey Literature guide to learn more.
- References: Reviewing reference lists from selected articles can turn up other studies that were missed during the searching phase.
- Hand Searching: This involves Identifying key journals for the topic and manually searching table of contents or using electronic journal search interface.
- Citing Papers: Reviewing citing papers from key relevant studies on the topic may yield additional results not captured. Citation resources include Google Scholar, Web of Science, and Scopus. Refer to the Database Searching tab to learn more about these tools and how to use them.
The resources listed below detail types and access points for various types of grey literature. Including grey literature sources has been demonstrated to have an impact on findings in several studies.