Ke Xu Junwei Cao Lianchen Liu Cheng Wu Performance Optimization of Temporal Reasoning for Grid Workflows Using Relaxed Region Analysis. 187-194 2008 AINA Workshops http://doi.ieeecomputersociety.org/10.1109/WAINA.2008.48 conf/aina/2008w db/conf/aina/ainaw2008.html#XuCLW08