@article{FRIEDERICH13_ACP,
   author = "F. Friederich and T. von Clarmann and B. Funke and H. Nieder
             and J. Orphal and M. Sinnhuber and G. P. Stiller and
             J. M. Wissing",
   title  = "Lifetime and production rate of {NO}$_x$ in the upper
             stratosphere and lower mesosphere in the polar spring/summer
             after the solar proton event in October-November 2003",
   journal= "Atmos. Chem. Phys.",
   volume = "13",
   number = "5",
   pages  = "2531-2539",
   doi    = "10.5194/acp-13-2531-2013",
   year   = "2013"   }