@article{butler:cgb,
  author = {Butler, S.},
  interhash = {f16d0b8f861076987ebb425f10d86702},
  intrahash = {0e4bb8ea8af8a8bf2a02aadddfaa24cd},
  title = {{Cospectral graphs for both the adjacency and normalized Laplacian matrices}},
  year = 2000
}