Chloe Rispal Olivier Carton Complementation of Rational Sets on Countable Scattered Linear Orderings. 381-392 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3340&spage=381 2004 conf/dlt/2004 Developments in Language Theory db/conf/dlt/dlt2004.html#RispalC04