OttoBib is a dead simple bibliography generator for book sources. Just enter ISBN codes of books separated by commas, select citation type (e.g. MLA, APA) and click "Get Citations". Thats it!
Using the Android's camera, the app "reads" a bookshelf, and with an AR overlay, quickly flags those books that are misplaced. It will also point to the correct place on the bookshelf so the book can easily be re-shelved correctly.