Jinshi Cui Hongbin Zha Huijing Zhao Ryosuke Shibasaki Laser-based detection and tracking of multiple people in crowds. 300-312 2007 106 Computer Vision and Image Understanding 2-3 http://dx.doi.org/10.1016/j.cviu.2006.07.015 db/journals/cviu/cviu106.html#CuiZZS07