1. GeoNames geographical database.
http://www.geonames.org/
2. Achtert, E., Goldhofer, S., Kriegel, H.-P., Schubert, E., Zimek, A.: Evaluation of Clusterings - Metrics and Visual Support.
http://elki.dbs.ifi.lmu.de/wiki/DataSets/MultiView
3. Arthur, V.: k-means++: The advantages of careful seeding. In: SODA 2007 (2007)
4. Asuncion: UCI machine learning repository (2007).
http://www.ics.uci.edu/mlearn/MLRepository.html
5. Baudry, J.-P., Celeux, G.: EM for mixtures. Stat. Comput. 25(4), 713–726 (2015)