Jingtao Yang Corina Cîrstea Peter Henderson Document Flow Model: A Formal Notation for Modelling Asynchronous Web Services Composition. 39-48 2005 conf/otm/2005-1 OTM Workshops http://dx.doi.org/10.1007/11575863_19 db/conf/otm/otm2005-1.html#YangCH05