1. Homeland Security Working Group, Symbology Reference, version 2.20 (released September 14, 2005)
2. Agarawala, A., Balakrishnan, R.: Keepin’ it real: Pushing the desktop metaphor with physics, piles and the pen. In: CHI 2006 - the ACM Conf. on Human Factors in Computing Systems, pp. 1283–1292 (2006)
3. Alvarado, C., Davis, R.: SketchREAD: A multi-domain sketch recognition engine. In: Proc. of the 17th annual ACM symposium on user interface software and technology, Santa Fe, New Mexico, USA, pp. 23–32 (2004)
4. Benoit, C., Martin, J.-C., Pelachaud, C., Schomaker, L., Suhm, B.: Audio-visual and multimodal speech-based systems. In: Gibbon, D., Mertins, I., Moore, R. (eds.) Handbook of multimodal and spoken dialogue systems: Resources, terminology and product evaluation, pp. 102–203. Kluwer Academic Publishers, Dordrecht (2000)
5. Bhaskarabhatla, A.S., Madhvanath, S.: Experiences in collection of handwriting data for online handwriting recognition in Indic scripts. In: Proc. of the 4th Int. Conf. Linguistic Resources and Evaluation (LREC), CDROM (2004)