Advances in Self-Organizing Maps, Learning Vector Quantization, Clustering and Data Visualization: Proceedings of the 13th International Workshop, WSOM+ 2019, Barcelona, Spain, June 26–28, 2019 - Vellido, Alfredo; Angulo, Cecilio; Gibert, Karina; Martín Guerrero, José David (Springer International Publishing, 2020)