@article{CTT100668094,
  author = {Kengo Oka and Koichiro Nabetani and Chika Sakaguchi and Hayato Seki and Michel  Czapski and Yuichi Shimakawa and Masaki Azuma},
  title = {Tuning negative thermal expansion in Bi<sub>1</sub>-<sub>X</sub>Ln<sub>X</sub>NiO<sub>3</sub>(Ln=La,Nd,Eu,Dy)},
  journal = {APPLIED PHYSICS LETTERS},
  year = 2013,
}

@article{CTT100631999,
  author = {Masaki Azuma and Wei-tin Chen and Hayato  seki and Michal  Czapski and Smirnova olga and Kengo oka and Masaichiro Mizumaki and Tetsu Watanuki and Naoki Ishimatsu and Naomi Kawamura and Shintaro Ishiwata and Matthew G. Tucker and Yuichi Shimakawa and J. Paul Attfield},
  title = {Colossal negative thermal expansion in BiNiO3 induced by intermetallic charge transfer},
  journal = {NATURE COMMUNICATIONS},
  year = 2011,
}