@article{SCHWARZ02,
   author = "G. Schwarz and S. Hilgers and H. Kemnitzer and T. Steck and 
             T. von Clarmann and M. H{\"o}pfner and K. Ressel",
   title  = "Sequential and Joint Retrieval of Trace Gas Profiles",
   journal= "Adv. Space. Res.",
   volume = "29",
   number = "11",
   pages  = "1649-1654",
   year   = "2002"   }