@article{lee1994building,
  title={Building skeleton models via 3-D medial surface axis thinning algorithms},
  author={Lee, Ta-Chih and Kashyap, Rangasami L and Chu, Chong-Nam},
  journal={CVGIP: Graphical Models and Image Processing},
  volume={56},
  number={6},
  pages={462--478},
  year={1994},
  publisher={Elsevier}
}

@article{blum1967transformation,
  title={A transformation for extracting new descriptions of shape},
  author={Blum, Harry},
  journal={Models for the perception of speech and visual form},
  pages={362--380},
  year={1967},
  publisher={MIT press}
}

@article{blum1973biological,
  title={Biological shape and visual science (Part I)},
  author={Blum, Harry},
  journal={Journal of theoretical Biology},
  volume={38},
  number={2},
  pages={205--287},
  year={1973},
  publisher={Elsevier}
}

@article{blum1978shape,
  title={Shape description using weighted symmetric axis features},
  author={Blum, Harry and Nagel, Roger N},
  journal={Pattern recognition},
  volume={10},
  number={3},
  pages={167--180},
  year={1978},
  publisher={Elsevier}
}