Yibing Song Yongtian Yang Chuangang Zhu Formalization of Capability for Command-Based Agent. 195-199 2006 conf/IEEEicci/2006 IEEE ICCI http://dx.doi.org/10.1109/COGINF.2006.365696 db/conf/IEEEicci/IEEEicci2006.html#SongYZ06