PAN campaigns,, \cite{Kasprzak2010}, \cite{Kasprzak2009a}:\r
\r
We detect {\it common features} between source and suspicious documents,\r
PAN campaigns,, \cite{Kasprzak2010}, \cite{Kasprzak2009a}:\r
\r
We detect {\it common features} between source and suspicious documents,\r