@article{PietrallaWalzScheitetal.2016,
  author    = {Norbert Pietralla and Christopher Walz and Heiko Scheit and Thomas Aumann and Ronan Lefol and V. Ju. Ponomarev},
  title     = {First observation of the competitive double-gamma ("γγ/γ") decay process},
  journal   = {The European physical journal. Web of Conferences},
  volume    = {107},
  number    = {art. 03002},
  pages     = {1 -- 6},
  doi       = {10.1051/epjconf/201610703002},
  year      = {2016},
}