1. About Robocup.
http://www.robocup.org/about-robocup/
. Accessed 20 June 2014
2. Small Size Robot League - start.
http://robocupssl.cpe.ku.ac.th/
. Accessed 20 June 2014
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4. Tamaki, T., Sugino, S., Yamamoto, M.: Measuring ball spin by image registration. In: Proceedings of the 10th Korea-Japan Joint Workshop on Frontiers of Computer Vision : FCV 2004, pp. 269–274 (2004)
5. Liu, C., Hayakawa, Y., Nakasima, A.: An on-line algorithm for measuring the translational and rotational velocities of a table tennis ball. SICE J. Control Meas. Syst. Integr. 5(4), 233–241 (2012)