@article{MacdonaldOteroButler2021,
  author    = {Elena Macdonald and Noelia Otero and Tim Butler},
  title     = {A comparison of long-term trends in observations and emission inventories of NOx},
  journal   = {Atmospheric chemistry and physics / European Geosciences Union},
  volume    = {21},
  number    = {5},
  pages     = {4007 -- 4023},
  doi       = {10.5194/acp-21-4007-2021},
  year      = {2021},
}