@article{11495,
  author = {P. Wilson},
  title = {The structure of a sunspot II: The Magnetohydrodynamics of the Penumbra},
  year = {1968},
  journal = {Solar Physics},
  volume = {3},
  pages = {454-465},
  month = {Jan-03-1968},
  issn = {0038-0938},
  url = {http://www.springerlink.com/index/pdf/10.1007/BF00171619},
  doi = {10.1007/BF00171619},
}