@article{11494,
  author = {P. Wilson},
  title = {The structure of a sunspot. I: The Birth and Development of a Sunspot},
  year = {1968},
  journal = {Solar Physics},
  volume = {3},
  pages = {243-257},
  month = {Jan-02-1968},
  issn = {0038-0938},
  doi = {10.1007/BF00155160},
}