Hans Weigand Paul Johannesson Birger Andersson Maria Bergholtz Ananda Edirisuriya Tharaka Ilayperuma On the Notion of Value Object. 321-335 2006 conf/caise/2006 CAiSE http://dx.doi.org/10.1007/11767138_22 db/conf/caise/caise2006.html#WeigandJABEI06