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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).
+In this exercise, you will learn how to cite sources using the shared bibliography provided in this template, and how to control the citation style and reference formatting using `{cite}` roles and the `{bibliography}` directive.
 
 ::::::{topic} Exercise objective
-Can you include references in your book using a bibliography file and cite them using different formats?
+Can you cite references using different in-line styles and customise the way your bibliography appears?
 ::::::
 
 ```{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.
 ````
 
+## Adding an entry to the shared bibliography
 
+1. The TeachBooks template already includes a shared bibliography file (`references.bib`). Locate and open the file. You will see the following example entry:
+
+```
+@misc{jason_moore,
+  title={Learn Multibody Dynamics, SymPy},
+  author={Moore, Jason},
+  howpublished={\url{https://moorepants.github.io/learn-multibody-dynamics/sympy.html}},
+  year={2023}
+}
+```
+
+2. Add a new reference of your own. You can use a DOI, book title, or URL.
 
 ```{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.
+You can generate BibTeX entries using free tools like [ZoteroBib](https://zbib.org). Paste a source URL or title, click **Cite**, and export as **BibTeX** to copy into `references.bib`.
 ```
 
-## Citing sources in different formats
+## Citing sources using `{cite}`
 
-5. To cite a source in numeric style (default when using `unsrt`), use `[@key]`. Try the following example:
+3. To reference a source in-line, use one of the `{cite}` roles. Try the following:
 
 ```md
-Einstein's paper on relativity changed physics [@einstein1905].
+{cite:p}`jason_moore`
 ```
 
+4. You can also use other variants of `{cite}` depending on the style you want. Try adding the following to your Markdown file and see how the output differs:
 
-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.
+* `{cite:p}`
+* `{cite:t}`
+* `{cite:ps}`
+* `{cite:ts}`
+
+```{dropdown} Hint: What to expect when you render these
+:class: hint
+
+Here’s how the citation will appear for the example in the shared bibliography:
+
+- `{cite:p}` → **Parenthetical citation**  
+  → [Moore, 2023]
+
+- `{cite:t}` → **Textual citation**  
+  → Moore [2023]
+
+- `{cite:ps}` → **Parenthetical, full authors**  
+  → [Moore, 2023]
+
+- `{cite:ts}` → **Textual, full authors**  
+  → Moore [2023]
+
+> You can experiment with different reference styles in your `_config.yml` file to change how these look.
+```
+
+## Displaying the bibliography
+
+5. To show the list of cited references at the end of the page, use the `{bibliography}` directive:
 
 ````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...
+`````{admonition} Avoiding duplicate citation warnings
+:class: note
+
+If you use `{bibliography}` in multiple files, you might see warnings about duplicate citations when building your book. To avoid this, restrict the bibliography to only show references cited in the current page by adding a `:filter:` option:
+
+````md
+```{bibliography}
+:filter: docname in docnames
 ```
 
-8. You can also site multiple references by separating them with semicolons:
+````
 
-```md
-Several foundational works include [@einstein1905; @knuth1984].
+This ensures only local references are shown, and avoids build-time warnings.
+`````
+
+
+## Customising citation styles
+
+
+6. You can change the **reference style** (how citations appear in your text) by editing the `_config.yml` file in your book folder. Add or modify the following section, and see how the referece style changes.
+
+```yaml
+sphinx:
+  config:
+    bibtex_reference_style: author_year
 ```
 
+7. Try replacing `author_year` with the following and see how the citation outputs change:
 
-## Rendering the bibliography
+* `author_year`
+* `label`
+* `super`
+* `number`
 
-9. At the bottom of the page (or wherever appropriate), include a `{bibliography}` directive to render the list of references:
+```{dropdown} Hint: What each reference style will look like
+:class: hint
+
+Heres's how each style will appear for the example in the shared bibliography:
+
+- `author_year` → Moore (2023)
+- `label` → [jason_moore]
+- `super` → ¹
+- `number` → [1]
+
+```
+
+8. You can also change the **bibliography style** (how the reference list is formatted) using the `:style:` option in the `{bibliography}` directive. Try replacing the style with the following, and see how the bibliography style changes.
 
 ````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)
+9. Experiment with the following different styles, and see how the bibliography style changes:
+
+- `alpha`
+- `plain`
+- `unsrt`
+- `unsrtalpha`
+
+```{dropdown} Hint: What each bibliography style looks like
+:class: hint
+
+Heres's how each style will appear for the example in the shared bibliography:
+
+- `alpha` → References labelled as [Knu84], sorted by author/year
+- `plain` → References numbered [1], sorted by author/year
+- `unsrt` → Numbered [1], in order of appearance in the text
+- `unsrtalpha` → Alphanumeric like [Knu84], but in order of appearance
+
 ```
 
-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.
+```{admonition} Bibliography style vs. Reference style
+:class: note
 
-13. Add a commit message.
+- **Reference style** controls how citations look in your text (e.g., [1] vs. (Author, Year)).
+- **Bibliography style** controls how the reference list is formatted (e.g., sorted, numbered, APA).
+```
 
-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).
+10. When you are ready, commit your changes to the repository by clicking on the green `Commit changes` button.
 
-15. Do you see your change? If you don't see it click `CTRL`+`F5`/`Control`+`F5`to refresh the page.
+11. Add a commit message.
+
+12. 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).
+
+13. 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.
+- How to add a new reference to the shared `references.bib` file.
+- How to use `{cite}` roles to control in-line citation appearance.
+- How to change the citation style in `_config.yml`.
+- How to display the bibliography with `{bibliography}`.
 ```
+