- Idea for songbook cover: http://upload.wikimedia.org/wikipedia/commons/e/e2/V%C3%A5rt_land_-_front_page.jpg
- Somewhere to start with Bluetooth 4 Smart: https://blog.gruby.com/2013/01/07/using-my-bluetooth-knowledge/
- More on Bluetooth BLE: http://rexstjohn.com/bluetooth-smart-ble-scanning-on-osx-xcode-6/