F. Benevenuto, T. Rodrigues, M. Cha, и V. Almeida. Proceedings of the 9th ACM SIGCOMM Conference on Internet Measurement Conference, стр. 49--62. New York, NY, USA, ACM, (2009)
D. Abrams, R. Baecker, и M. Chignell. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, стр. 41--48. New York, NY, USA, ACM Press/Addison-Wesley Publishing Co., (1998)