This is not a book recommendation but I strongly advice you to use some existing frameworks for your CMS.

• OpenInteract
• XML::Comma
• AxKit

Templating:

• Template
• HTML::Template
• HTML::Mason

Or you could analyze if some existing Open Source CMS could not be a bit twinked to fit to your requirements:

• Bricolage
• Callisto

Some related resources you can find in my node Collaborative Media.