Interactive book : any way to do some very minimal branching ?

I have a question about the intearctive book. 

I need some way of presenting content that is a little bit "book like" and that embeds tests. So far so good.

I would like to get some minimal branching though, very minimal, just to link to some (a paragraph or two) additional more specialized content.

I understand that I could use a link with an url to a page within the book (let's say at the last page of the interactive book), but moving the interactive

book elsewhere would break the url link. Not a good idea in the long run.

I could also add a true/false question "Would you like to get more info on this question ?" and if the student clicked on "yes", the more specialized content would appear as a comment on the "yes" answer. But thus would be very inelegant : most questions would be for testing content, a few others, once in a while, would not be.

Any suggestions ? Thanks.

-Pierre