1. Number of Smartphone Users Worldwide from 2012 to 2019http://de.statista.com/statistik/daten/studie/309656/umfrage/prognose-zur-anzahl-der-smartphone-nutzer-weltweit/
2. Grundkurs Mobile Kommunikationssysteme: LTE-Advanced, UMTS, HSPA, GSM, GPRS, Wireless LAN und Bluetooth;Sauter,2015
3. Getting Started with Bluetooth Low Energy: Tools and Techniques for Low-Power Networking;Townsend,2014