Bernd Borchert Klaus-Jörn Lange Frank Stephan Pascal Tesson Denis Thérien The Dot-Depth and the Polynomial Hierarchy Correspond on the Delta Levels. 89-101 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3340&spage=89 2004 conf/dlt/2004 Developments in Language Theory db/conf/dlt/dlt2004.html#BorchertLSTT04