J. Mackinlay, R. Rao, and S. Card. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, page 67--73. New York, NY, USA, ACM Press/Addison-Wesley Publishing Co., (1995)
M. Baldonado, and T. Winograd. Proceedings of the ACM SIGCHI Conference on Human Factors in Computing Systems, page 11--18. New York, NY, USA, ACM, (1997)
M. Morris, and E. Horvitz. Proceedings of the 20th annual ACM symposium on User interface software and technology, page 3--12. New York, NY, USA, ACM, (2007)