Wei Shi Jian Wu Shaolin Zhou Ling Zhang Yuyu Yin Zhaohui Wu Facilitating the Flexible Modeling of Human-Driven Workflow in BPEL. 1615-1624 2008 AINA Workshops http://doi.ieeecomputersociety.org/10.1109/WAINA.2008.26 conf/aina/2008w db/conf/aina/ainaw2008.html#ShiWZZYW08