H.  Spies and Scharr, H., ?Accurate optical flow in noisy image sequences?, in ICCV, 2001, p. 587--592.

H.  Spies, ?Analysing Dynamic Processes in Range Data Sequences?. IWR, Fakultät für Physik und Astronomie, Univ.\ Heidelberg, 2001.

H.  Spies, Gröning, H., Haußecker, H., Jähne, B., and Haußecker, H., ?Analyzing particle movements at soil interfaces?, Computer Vision and Applications. A Guide for Students and Practitioners. Academic Press, p. 648--649, 2000.

H.  Spies, Beringer, O., Gröning, H., Haußecker, H., Jähne, B., Haußecker, H., and Geißler, P., ?Analyzing particle movements at soil interfaces?, Handbook of Computer Vision and Applications, vol. 3: Systems and Applications. Academic Press, pp. 699-718, 1999.