Customizing Bookreader viewer

Hi there,
I would like to add a couple of custom links to the BookReader plugin viewer. Any suggestions for how to do this? I'm guessing I will need to edit in the plugin file itself.

Hi,

What is a custom url ? Do you have an example? The bookreader can be customized in your theme too.

Sincerely,

Daniel Berthereau
Infodoc & Knowledge management

I have couple of links - links to another collection but also a link to a brief guide about how to use the bookreader (google doc).

Thanks I am going to take a look at theme files.