@article{4382,
  author = {N. Walborn and Edward Fitzpatrick},
  title = {Contemporary optical spectral classification of the OB stars - A digital atlas},
  year = {1990},
  journal = {Publications of the Astronomical Society of the Pacific},
  volume = {102},
  pages = {379},
  month = {Jan-12-1990},
  issn = {0004-6280},
  url = {http://articles.adsabs.harvard.edu/full/1990PASP..102..379W},
  doi = {10.1086/132646},
}