@article{10725,
  author = {G. Wallerstein and E. Brugel},
  title = {The absolute magnitude of the field population. II - Cepheid XX Virginis},
  year = {1979},
  journal = {The Astronomical Journal},
  volume = {84},
  pages = {1840},
  month = {Jan-12-1979},
  issn = {00046256},
  url = {http://articles.adsabs.harvard.edu/full/1979AJ.....84.1840W},
  doi = {10.1086/112615},
}