It’s important to know how to find relevant sources when writing a research paper, literature review, or systematic review.

The types of sources you need will depend on the stage you are at in the research process, but all sources that you use should be credible, up-to-date, and relevant to your research topic. There are three main places to look for sources to use in your research:

• Research databases

• Your institution’s library

• Other online resources

Research databases

You can search for scholarly sources online using databases and search engines like Google Scholar. These provide a range of search functions that can help you to find the most relevant sources. If you are searching for a specific article or book, include the title or the author’s name. Alternatively, if you’re just looking for sources related to your research problem, you can search using keywords. In this case, it’s important to have a clear understanding of the scope of your project and of the most relevant keywords. Databases can be general (interdisciplinary) or subject-specific.

• You can use subject-specific databases to ensure that the results are relevant to your field.

• When using a general database or search engine, you can still filter results by selecting specific subjects or disciplines.

Your institution’s library may have access to a range of academic databases and journals that are behind paywalls. Consult the library’s website to see if they have memberships with any journals relevant to your research.

Google Scholar

To get started, you might also try Google Scholar, an academic search engine that can help you find relevant books and articles. Its “Cited by” function lets you see the number of times a source has been cited. This can tell you something about a source’s credibility and importance to the field.

Boolean operators

Boolean operators can also help to narrow or expand your search. Boolean operators are words and symbols like AND, OR, and NOT that you can use to include or exclude keywords to refine your results. For example, a search for “Nietzsche NOT nihilism” will provide results that include the word “Nietzsche” but exclude results that contain the word “nihilism.”

Many databases and search engines have an advanced search function that allows you to refine results in a similar way without typing the Boolean operators manually.

Library resources

You can find helpful print sources in your institution’s library. These include:

• Journal articles

• Books

• Encyclopedias

• Newspapers and magazines

Make sure that the sources you consult are appropriate to your research. You can find these sources using your institution’s library database. This will allow you to explore the library’s catalog and to search relevant keywords. You can refine your results using Boolean operators. Once you have found a relevant print source in the library:

• Consider what books are beside it. This can be a great way to find related sources, especially when you’ve found a secondary or tertiary source instead of a primary source.

• Consult the index and bibliography to find the bibliographic information of other relevant sources.

Tip

Many libraries have an inter-library loan system that allows you to request specific books that the library does not stock. Consult a librarian if you are looking for a specific book that’s not available from your institution’s library.

Other online sources

You can consult popular online sources to learn more about your topic. These include:

• Websites

• Crowdsourced encyclopedias like Wikipedia

• Blogs

You can find these sources using search engines. To refine your search, use Boolean operators in combination with relevant keywords. However, exercise caution when using online sources. Consider what kinds of sources are appropriate for your research and make sure the sites are credible. Look for sites with trusted domain extensions:

• URLs that end with .edu are educational resources.

• URLs that end with .gov are government-related resources.

• DOIs often indicate that an article is published in a peer-reviewed, scientific article.

Other sites can still be used, but you should evaluate them carefully and consider alternatives.