Further details

"Local Velocity-Adapted Motion Events for Spatio-Temporal Recognition" (2007),
I. Laptev, B. Caputo, C. Schuldt and T. Lindeberg; in Computer Vision and Image Understanding, 108:207-229.
"Recognizing Human Actions: A Local SVM Approach" (2004),
Christian Schuldt, Ivan Laptev and Barbara Caputo; in Proc. ICPR'04, Cambridge, UK, pp.III:32--36.

PhD Thesis:
"Local Spatio-Temporal Image Features for Motion Interpretation" (2004),
Ivan Laptev; PhD Thesis, defended on June 11, 2004 at Computational Vision and Active Perception Laboratory (CVAP), NADA, KTH, Stockholm. ISBN 91-7283-793-4.

KTH human actions dataset.