@article{machinelearninginapogeeunsupervised,
  title = {Machine learning in APOGEE: Unsupervised spectral classification with $K$-means},
  author = {Rafael Garcia-Dias and Carlos Allende Prieto and Jorge Sánchez Almeida and Ignacio Ordovás-Pascual},
  year = {2018},
  eprint = {1801.07912},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1801.07912v2},
}