1. Bianchi, A., Oakley, I., Kostakos, V., Kwon, D.S.: The phone lock: audio and haptic shoulder-surfing resistant PIN entry methods for mobile devices. In: TEI 2011, pp. 197–20 (2011)
2. Kumar, M., Garfinkel, T., Boneh, D., Winograd, T.: Reducing shoulder-surfing by using gaze-based password entry. In: SOUPS 2007, pp. 13–19 (2007)
3. Luca, A.D., Harbach, M., Zezschwitz, E.v., Maurer, M.-E., Slawik, B.E., Hussmann, H., Smith, M.: Now you see me, now you don’t: protecting smartphone authentication from shoulder surfers. In: CHI 2014, pp. 2937–2946 (2014)
4. Shirazi, A.S., Moghadam, P., Ketabdar, H., Schmidt, A.: Assessing the vulnerability of magnetic gestural authentication to video-based shoulder surfing attacks. In: CHI 2012, pp. 2045–2048 (2012)
5. Wiedenbeck, S., Waters, J., Sobrado, L., Birget, J.-C.: Design and evaluation of a shoulder-surfing resistant graphical password scheme. In: AVI 2006, pp. 177–184 (2006)