@inproceedings{bridges2013:207,
  author      = {S\'{e}quin, Carlo H.},
  title       = {Cross-Caps---Boy Caps---Boy Cups},
  pages       = {207--216},
  booktitle   = {Proceedings of Bridges 2013: Mathematics, Music, Art, Architecture, Culture},
  year        = {2013},
  editor      = {Hart, George W. and Sarhangi, Reza},
  isbn        = {978-1-938664-06-9},
  issn        = {1099-6702},
  publisher   = {Tessellations Publishing},
  address     = {Phoenix, Arizona},

  url         = {http://archive.bridgesmathart.org/2013/bridges2013-207.html}
}