@article{JMLR:v20:18-456,
  author  = {Afonso Fernandes Vaz and Rafael Izbicki and Rafael Bassi Stern},
  title   = {Quantification Under Prior Probability Shift: the Ratio Estimator and its Extensions},
  journal = {Journal of Machine Learning Research},
  year    = {2019},
  volume  = {20},
  number  = {79},
  pages   = {1--33},
  url     = {http://jmlr.org/papers/v20/18-456.html}
}