Paper  bibtex   

@article{burks1949,
  author = {Arthur W. Burks},
  date = {1949},
  journaltitle = {Philosophy and Phenomenological Research},
  number = {4},
  pages = {673--689},
  title = {Icon, Index, and Symbol},
  url = {http://www.jstor.org/stable/2103298},
  volume = {9},
}