@article{RoeckmannBrassBorchersetal.2011,
  author    = {Thomas R{\"o}ckmann and Marc Brass and Reinhard Borchers and Andreas Engel},
  title     = {The isotopic composition of methane in the stratosphere : high-altitude balloon sample measurements},
  journal   = {Atmospheric chemistry and physics},
  volume    = {11},
  pages     = {13287 -- 13304},
  doi       = {10.5194/acp-11-13287-2011},
  year      = {2011},
}