1. Dhamija, R., Perrig, A.: Deja Vu: A User Study Using Images for Authentication. In: 9 th Usenix Security Symposium, August 2000, pp. 45–58 (2000)
2. Angeli, A.D., Coutts, M., Coventry, L., Johnson, G.I.: VIP: a visual approach to user authentication. In: Proc. of the Working Conference on Advanced Visual Interface (AVI 2002), May 2002, pp. 316–323 (2002)
3. Perrig, A., Song, D.: Hash Visualization: a New Technique to improve Real- World Security. In: International Workshop on Cryptographic Techniques and ECommerce, CrypTEC (1999)