@article{PietrallaWalzScheitetal.2016,
  author    = {Norbert Pietralla and Christopher Walz and Heiko Scheit and Thomas Aumann and Ronan Lefol and V. Yu. Ponomarev},
  title     = {First observation of the competitive double-gamma (γγ/γ) decay process},
  journal   = {Journal of physics. Conference Series},
  volume    = {724},
  number    = {art. 012039},
  doi       = {10.1088/1742-6596/724/1/012039},
  year      = {2016},
}