@conference{6956,
  author = {J. Yokogawa and K. Koyama and Y. Maeda and S. Skinner},
  title = {X-ray evidence for wind-wind collision in the Wolf-Rayet binary V444 Cygni},
  year = {1999},
  publisher = {San Francisco, Calif. : Astronomical Society of the Pacific},
  address = {Puerto Vallarta, Mexico},
  url = {http://adsabs.harvard.edu/full/1999IAUS..193..398Y},
  note = {JILA Pub. 6304},
}