Ella E. Roubtsova Jan van Katwijk Ruud C. M. de Rooij Hans Toetenel Transformation of UML Specification to XTG. 247-254 2001 conf/ershov/2001 Ershov Memorial Conference http://dx.doi.org/10.1007/3-540-45575-2_25 db/conf/ershov/ershov2001.html#RoubtsovaKRT01