@article{HelsperNiessner1985,
  author    = {Helsper, Christoph and Nießner, R.},
  title     = {On the Influence of the Vapour Substance on the Behaviour of an Expansion Type Condensation Nucleus Counter},
  series = {Journal of Aerosol Science. 16 (1985), H. 5},
  journal   = {Journal of Aerosol Science. 16 (1985), H. 5},
  isbn      = {0021-8502},
  pages     = {457 -- 461},
  year      = {1985},
  language  = {en}
}
@article{HelsperNiessner1985,
  author    = {Helsper, Christoph and Nießner, R.},
  title     = {Application of a Multistep Condensation Nuclei Counter as a Detector for Particle Surface Composition / Nießner, R. ; Helsper, C.},
  series = {Journal of Aerosol Science. 16 (1985), H. 3},
  journal   = {Journal of Aerosol Science. 16 (1985), H. 3},
  isbn      = {0021-8502},
  pages     = {201 -- 209},
  year      = {1985},
  language  = {en}
}