I have small bookdown 'book' that includes the following code:
A concept map is a diagram that shows 'ideas' and the relationship between those ideas. An example of a concept map is shown in Figure \@ref(fig:exampleCM).
```{r exampleCM, fig.show='hold', fig.cap='An example concept map --- Source: [Wikipedia](https://upload.wikimedia.org/wikipedia/commons/d/df/Conceptmap.png "Concept Map from Wikipedia")', echo=FALSE}
knitr::include_graphics('images/ConceptMap.png')
```
If I render the book as HTML everything works as expected. The caption includes a hyperlink to wikimedia/wikipedia. I.e., the caption looks like this:
Figure E.1: An example concept map — Source: Wikipedia
If I render the book as PDF, the caption in the PDF looks like this:
Figure E.1: An example concept map -- Source: [Wikipedia](https://upload.wikimedia.org/wikipedia/commons/d/df/Concep "Concept Map from Wikipedia")
It seems that the rmarkdown doesn't get rendered for some reason. The LaTeX file that is produced is like this:
A concept map is a diagram that shows `ideas' and the relationship between those ideas. An example of a concept map is shown in Figure \ref{fig:exampleCM}.
\begin{figure}
\includegraphics[width=12.33in]{images/ConceptMap} \caption{An example concept map --- Source: [Wikipedia](https://upload.wikimedia.org/wikipedia/commons/d/df/Conceptmap.png "Concept Map from Wikipedia")}\label{fig:exampleCM}
\end{figure}
I wonder how I might fix this.
