2014 · Sjoerd Beugelsdijk, Björn Jindra, et al. · University of Groningen research database (University of Groningen / Centre for Information Technology)
2013 · Dut Van Vo, Sjoerd Beugelsdijk, et al. · University of Groningen research database (University of Groningen / Centre for Information Technology)
2012 · Dut Van Vo, Sjoerd Beugelsdijk, et al. · University of Groningen research database (University of Groningen / Centre for Information Technology)