App developers guide to eBook DRM

Hi HN, I have been googling around for a while, but it is proving notoriously difficult to get results.

I am working on designing an ebook reader, this reader will be cross platform including everything from computers to tablets (andriod and iOS).

A major concern here is DRM which limits which devices the user can use to read their ebook.

Does anybody know where I can find a developers guide to dealing with ebook DRM restrictions - particularly when designing an app that is aimed to be functional across multiple platforms.

Thanks for your help!