Nenad Dedic Gene Itkis Leonid Reyzin Scott Russell Upper and Lower Bounds on Black-Box Steganography. 227-244 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3378&spage=227 2005 conf/tcc/2005 TCC db/conf/tcc/tcc2005.html#DedicIRR05