@inproceedings{bridges2022:277,
  author      = {Hammack, Richard H.},
  title       = {Closed Surface Envelopes},
  pages       = {277--280},
  booktitle   = {Proceedings of Bridges 2022: Mathematics, Art, Music, Architecture, Culture},
  year        = {2022},
  editor      = {Reimann, David and Norton, Douglas and Torrence, Eve},
  isbn        = {978-1-938664-42-7},
  issn        = {1099-6702},
  publisher   = {Tessellations Publishing},
  address     = {Phoenix, Arizona},

  url         = {http://archive.bridgesmathart.org/2022/bridges2022-277.html}
}