ure.Rmd`

```r
# Literature

Here is a review of existing methods.
```

]

.pull-right[
### Prerequisites

This is a _sample_ book written in **Markdown**. 
&lt;hr&gt;
### Chapter 1  Introduction

Blah blah blah.
&lt;hr&gt;
### Chapter 2  Literature

Here is a review of existing methods.
]

???

You can un-number a chapter by following the header text with curly brackets, with .unnumbered, like I did for "Prerequisites" here.


---
class: middle
name: headers-cross

## .center[.fancy[Label &amp; Cross-Refer