Piotr Dembinski Jan Maluszynski Attribute Grammars and Two-Level Grammars: A Unifying Approach. 143-154 1978 conf/mfcs/1978 MFCS db/conf/mfcs/mfcs78.html#DembinskiM78 http://dx.doi.org/10.1007/3-540-08921-7_63