PDF Reader with Urban Airship Subscriptions

For our first version we are content with an in-app subscription / individual in-app purchases. Once the user buys the subscription the PDF file will be downloaded from Urban Airship to the application. From there I need the PDF to be opened with an open source PDF reader like: schwa/iOS-PDF-Reader - GitHub or vfr/Reader - GitHub. The user will be able to browse the PDF file and return to a Library screen that contains all of their purchased PDFs. When a user taps on any purchased item it should open in the PDF reader.