Links & references
GTM algorithm by Bishop et al: https://www.microsoft.com/en-us/research/wp-content/uploads/1998/01/bishop-gtm-ncomp-98.pdf
kernel GTM: https://www.elen.ucl.ac.be/Proceedings/esann/esannpdf/es2010-44.pdf
GTM classification models: https://www.ncbi.nlm.nih.gov/pubmed/24320683
GTM regression models: https://www.ncbi.nlm.nih.gov/pubmed/27490381
Visualizations were realized using altair
Source code: https://github.com/hagax8/ugtm