Sync outlook and Facebook events with Android App

Question

I am working on an app where users can manage/schedule their upcoming events events. So besides the events created on App, I need to sync the events from different calenders also like from Google Calender, Facebook Calender and Outlook Calender.

I know that the Google calender events can be synced by using Content provider but I don't have any idea how to sync calender events from Facebook and Outlook. Any help or guidance would be appreciated.