Anand, A., Bedathur, S., Berberich, K., & Schenkel, R.(2010). Efficient Temporal Keyword Queries over Versioned Text (MPI-I-2010-5-003). Saarbrücken: Max-Planck-Institut für Informatik. Retrieved from http://domino.mpi-inf.mpg.de/internet/reports.nsf/NumberView/2010-5-003.