Add referencing instructions

docs/referencing.md

@@ -1 +1,33 @@
 # Referencing
+
+Referencing is powered by `pandoc-citeproc`, so any format supported by it is supported. A list of supported formats can be found [here](https://github.com/jgm/pandoc-citeproc/blob/master/man/pandoc-citeproc.1.md).
+
+__Remember__: To use YAML, your file must end `.yaml` rather than `.yml`!
+
+## CSL Files
+There are many different ways of referencing, both inline, and in a bibliography. `md-pdf` supports _all_ of them.
+
+The configuration used for this is stored in `csl` files, which can be downloaded through `md-pdf`. See the usage instructions on how to download these.
+
+There's a full list of available `csl` files [here](https://github.com/citation-style-language/styles/).
+
+## Example
+Assuming youre using the same bibliography as the example, an input of:
+
+```markdown
+@item1 says blah.
+```
+Will render as:
+```
+Doe (2005) says blah.
+```
+
+### Advanced Citation
+You can also use more advanced referencing to be more specific:
+```markdown
+A citation group [see @item1 p. 34-35; also @item3 chap. 3].
+```
+will result in:
+```
+A citation group (see Doe 2005, 34–35; also Doe and Roe 2007, chap. 3)
+```

test-files/mdp.yml

@@ -5,7 +5,7 @@ output_formats:
 output_dir: out/
 bibliography:
   references: bib.yaml
-  csl: apa
+  csl: chicago-author-date
 context:
   foo: bar
   bar: foo