Before revision:  ~\mbox{%DIFAUXCMD \cite{bcg-ffq-13}\hspace{0pt}%DIFAUXCMD } [ [ \eps\eps .
After revision:  ~\mbox{%DIFAUXCMD \cite{bcg-ffq-13}\hspace{0pt}%DIFAUXCMD } [ . We also revisit the time-window data structure for spatial density maps in[ \eps\eps .