exercise 13

Author: katiagatt

book/_toc.yml

@@ -25,6 +25,7 @@ parts:
       - file: syntax_exercises/010.md
       - file: syntax_exercises/011.md
       - file: syntax_exercises/012.md
+      - file: syntax_exercises/013.md
     - file: references.md
     - file: changelog.md
     - file: credits.md

book/syntax_exercises/013.md

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+# Exercise 13: Adding a Bibliography
+
+In this exercise, you will learn how to add a bibliography to your book and how to include references to sources using different citation styles (e.g., numeric, author–year, or label-based).
+
+\::::::{topic} Exercise objective
+Can you include references in your book using a bibliography file and cite them using different formats?
+\::::::
+
+```{tip}
+Citing references properly gives credit to original authors and improves your writing. See the [JupyterBook guide on citations](https://jupyterbook.org/en/stable/content/citations.html) for full details.
+```
+
+## Adding a bibliography
+
+1. Open or create a Markdown file where you want to use references.
+
+2. Make sure a bibliography file exists in your project. The default format is `.bib`, which uses BibTeX syntax. You can create a file called `references.bib` in the root or relevant folder of your project. 
+
+3. In the `references.bib` file, and add entries to reference like the examples below.
+
+```
+@book{knuth1984,
+  author    = {Donald E. Knuth},
+  title     = {The TeXbook},
+  year      = {1984},
+  publisher = {Addison-Wesley}
+}
+
+@article{einstein1905,
+  author  = {Einstein, Albert},
+  title   = {On the Electrodynamics of Moving Bodies},
+  journal = {Annalen der Physik},
+  year    = {1905}
+}
+```
+4. Return to the Markdown file you are working on, and link the bibliography file using a **front matter header**. This should be placed at the very top of your file to automatically enable citations and bibliography rendering:
+
+```md
+---
+bibliography: references.bib
+---
+```
+
+````{admonition} What is a front matter header?
+:class: note
+
+A front matter header is a block of configuration settings written in YAML and placed at the very top of a Markdown file, enclosed between triple dashes `---`. It allows you to specify page-level options such as the title, tags, or the bibliography file to use.
+
+For example, the following tells Jupyter Book to use `references.bib` for any citations on that page:
+
+```yaml
+---
+bibliography: references.bib
+---
+```
+````
+
+
+
+```{tip}
+You can add this `bibliography:` key in `_config.yml` to make the reference file available to the whole book instead of just per page.
+```
+
+## Citing sources in different formats
+
+5. To cite a source in **numeric style** (default when using `unsrt`), use `[@key]`. Try the following example:
+
+```md
+Einstein's paper on relativity changed physics [@einstein1905].
+```
+
+
+6. To cite a source in **author–year style**, change the style to `author-year` as shown below. Try this out and see how the citation from the previous step changes to the new formatting style.
+
+````md
+```{bibliography}
+:style: author-year
+:filter: False
+```
+````
+
+
+7. You can also write inline references using `@key`, which will automatically expand to author/year or number depending on the style. Try this out:
+
+```md
+@einstein1905 describes special relativity...
+```
+
+8. You can also site **multiple references** by separating them with semicolons:
+
+```md
+Several foundational works include [@einstein1905; @knuth1984].
+```
+
+
+## Rendering the bibliography
+
+9. At the bottom of the page (or wherever appropriate), include a `{bibliography}` directive to render the list of references:
+
+````md
+```{bibliography}
+:style: unsrt
+```
+````
+
+```{tip}
+You can use `:style:` to choose different reference formats. Common options include:
+- `unsrt` (numerical, unsorted)
+- `plain` (numerical, sorted)
+- `author-year` (author/date)
+- `apa`, `ieee`, `nature` (other standard citation styles)
+```
+
+10. Ensure your `.bib` file is correctly formatted and that each key used in `@key` or `[@key]` matches an entry in that file. If a reference doesn’t show up, double-check the syntax or run the build process again.
+
+12. When you are ready, commit your changes to the repository by clicking on the green `Commit changes` button.
+
+13. Add a commit message.
+
+14. To see your changes, go to {octicon}`play` `Actions` - The most recent workflow run `overview.md / the commit message of the commit you just made` - Wait for it to finish - In the summary, click on the link of your book shown in the table `Branches deployed` and under `Primary book at root` (getting bored of waiting? There'll be exercising on doing this locally which prevents you from waiting).
+
+15. Do you see your change? If you don't see it click `CTRL`+`F5`/`Control`+`F5`to refresh the page.
+
+
+```{admonition} Check your understanding
+:class: note
+
+Before moving on, make sure you understand:
+- How to include and link a bibliography file.
+- How to cite a reference using `@key` and `[@key]`.
+- How to switch between citation styles like numeric or author–year.
+- How to render the bibliography list at the bottom of a page.
+```