1. 1. Charles severance, "Eben upton: Raspberry pi", published by IEEE computer society, October 2013.
   2. Valeriu, Florin and Adrian-Viorel, Control System for Video Advertising Based on Raspberry Pi, 2014.
   3. http://codeduino.com/tutorials /arduino-vsraspberry-pi/news /hardware/arduino-vsraspberry-pi/
   4. http://www.zdnet.com/raspberry-pi-11 -reasonswhy-its-the-perfect-small -server-70000 206/
   5. J. Long and J. Wiles, No Tech Hacking: A 6u/de to Sac/ a/ Engineering,Dumpster Diving and Shoulder Surfing. Boston, MA, U : ng re . 2008.
   6. T. Kwon and J. Hong, "Analysis and improvement of a PIN entry method resilient to shoulder-surfing and recording attacks," IEEE Trans. Inf Forensics security, vol. 10, no. 2, pp. 278-292, Feb. 2015.