@inproceedings{Choi_VSWS_2009,
author = {Wongun Choi and Khuram Shahid and Silvio Savarese},
title = { What are they doing? : Collective Activity Classification Using Spatio-Temporal Relationship Among People},
booktitle = {Proc. of 9th International Workshop on Visual Surveillance (VSWS09) in conjuction with ICCV},
year = {2009}
}