The docstring for one of the Python sample programs includes a link to the research paper describing the main algorithm. That link is no longer valid (results in a 404 error) so this update replaces it with another link from the same institution which is currently valid.
c - clear targets
[1] David S. Bolme et al. "Visual Object Tracking using Adaptive Correlation Filters"
- http://www.cs.colostate.edu/~bolme/publications/Bolme2010Tracking.pdf
+ http://www.cs.colostate.edu/~draper/papers/bolme_cvpr10.pdf
'''
# Python 2/3 compatibility