1. BerlinMOD. http://dna.fernuni-hagen.de/secondo/BerlinMOD.html
2. Nearest Neighbor Algebra Plugin. http://dna.fernuni-hagen.de/Secondo.html/files/plugins/NN.zip
3. R-tree Portal. http://www.rtreeportal.org
4. Scripts to execute the experiments of this paper. http://dna.fernuni-hagen.de/papers/KNN/knn-experiment-script.zip
5. Secondo. A Database System for Moving Objects. http://dna.fernuni-hagen.de/Secondo.html/Secondo-mod.pdf