@article{quantum-walks-and-the-size-of-the-graph,
  title = {{Quantum walks and the size of the graph}},
  author = {G Coutinho},
  year = {2019},
  journal = {Discrete Mathematics 2019},
  eprint = {1802.08734},
  archivePrefix = {arXiv},
  url = {https://www.sciencedirect.com/science/article/abs/pii/S0012365X1830116X}
}