@article{Obers:19997Z,
  author = "Obers, Niels  and  Pioline, Boris",
  title = "{M- Theory and U - dualities}",
  doi = "10.22323/1.001.0053",
  journal = "PoS",
  year = 1999,
  volume = "corfu98",
  pages = "053"
}