Julian Rathke Vladimiro Sassone Pawel Sobocinski Semantic Barbs and Biorthogonality. 302-316 2007 conf/fossacs/2007 FoSSaCS http://dx.doi.org/10.1007/978-3-540-71389-0_22 db/conf/fossacs/fossacs2007.html#RathkeSS07