Distance metrics and evaluating clusters:
- Evaluation of clustering overview: https://nlp.stanford.edu/IR-book/html/htmledition/evaluation-of-clustering-1.html
- A comparison of various distance/similarity metrics: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0144059
- Visualizing k-means clustering: https://www.naftaliharris.com/blog/visualizing-k-means-clustering/
- github.com/mash/gokmeans docs: https://godoc.org/github.com/mash/gokmeans