@article{demaine2007jigsaw,
  title={Jigsaw puzzles, edge matching, and polyomino packing: Connections and complexity},
  author={Demaine, Erik D. and Demaine, Martin L.},
  journal={Graphs and Combinatorics},
  volume={23},
  number={1},
  pages={195--208},
  year={2007},
  publisher={Springer}
}

@article{altman1989solving,
  title={Solving the jigsaw puzzle problem in linear time},
  author={Altman, Tom},
  journal={Applied Artificial Intelligence an International Journal},
  volume={3},
  number={4},
  pages={453--462},
  year={1989},
  publisher={Taylor \& Francis}
}