In the beta version of Papers, Please, the recurring character Jorji Costava's ID reference was MR_PERSISTENT
There is an ISBN13 code at the end of the in-game rulebook (978-0-452-28423-4). It is the same code as the centennial edition of George Orwell's novel 1984.
Before release, the developers accepted submissions for names for the game's randomly-generated characters, a decision they later regretted. One of the submitted names was that of Anita Sarkeesian, author of the video blog "Feminist Frequency", but her name was removed when a fan told the developer that her name was used for a stripper.