D. Cox, V. Kindratenko, and D. Pointer. UbiComp 2003: Ubiquitous Computing, volume 2864 of Lecture Notes in Computer Science, Springer, Berlin / Heidelberg, (2003)
N. Koeppen, K. Polkehn, and H. Wandke. Measuring Behavior 2002, 4th International Cofnerence on
Methods and Techniques in Behavioral Research, 27-30 August 2002, Amsterdam, (2002)