I'm looking for a book reading app that would allow me to have more than one book open at a time, do you know of any, please? For example, the Windows version of Nook Reader allows you to open books in different tabs, almost like Chrome can open webpages in different tabs. It will be used as a study aid, allowing me to make cross references between two, or as many books as the reader will allow. Do you know of any readers that do this, please? Thanks for any advice.