H. Takagi, C. Asakawa, K. Fukuda, and J. Maeda. Assets '04: Proceedings of the 6th international ACM SIGACCESS conference on Computers and accessibility, page 177--184. New York, NY, USA, ACM, (2004)
P. Pyla, J. Howarth, C. Catanzaro, and C. North. ACM-SE 44: Proceedings of the 44th annual Southeast regional conference, page 620--625. New York, NY, USA, ACM, (2006)