Something is off about this story. A brief glance in the iBookstore shows tons of books on Amazon and Amazon products, including books on how to sell your work via Amazon. We're talking entire books who's sole purpose is to promote or support the use of Amazon. Clearly Apple has no problem with those.
> Book file contains links from competitors: Amazon, in the chapter Q&A 6, under “Question 9″
I'm sure books dedicated to Amazon will contain links to them, so I think this just adds a little bit more evidence to the stories of Apple's inconsistent review process.