@article{bhandari,
  title = {Imaging electron flow from collimating contacts in graphene},
  author = {S Bhandari, G H Lee, K Watanabe, T Taniguchi, P Kim, R M Westervelt},
  publisher = {IOP Publishing},
  year = {2018},
  keywords = {Ballistic electrons, graphene, electron-optic devices}
}