2001 · A.B. Dijkstra, Karsten Schuldt, et al. · University of Groningen research database (University of Groningen / Centre for Information Technology) · 18
2017 · Veldkamp, Bernard P.; id_orcid 0000-0003-3543-2164, Schildkamp, Kim ; id_orcid 0000-0001-6154-6857, et al. · University of Twente Research Information · 2
2003 · Adrie J. Visscher, Anne Bert Dijkstra, et al. · University of Groningen research database (University of Groningen / Centre for Information Technology) · 1