Wojciech Czerwinski Claire David Katja Losemann Wim Martens Deciding Definability by Deterministic Regular Expressions. 289-304 2013 FoSSaCS https://doi.org/10.1007/978-3-642-37075-5_19 conf/fossacs/2013 db/conf/fossacs/fossacs2013.html#CzerwinskiDLM13