@article{CTT100609222,
  author = {H. Shimotani and H. Asanuma and A. Tsukazaki and A. Ohtomo and M. Kawasaki and Y. Iwasa},
  title = {Insulator-to-metal transition in ZnO by electric double layer gating},
  journal = {Applied Physics Letters},
  year = 2007,
}