@article{HelsperMoelterHaller1990,
  author    = {Helsper, Christoph and M{\"o}lter, W. and Haller, P.},
  title     = {Representative Dilution of Aerosols by a Factor of 10,000},
  series = {Journal of Aerosol Science. 21 (1990), H. Suppl. 1},
  journal   = {Journal of Aerosol Science. 21 (1990), H. Suppl. 1},
  isbn      = {0021-8502},
  pages     = {637 -- 640},
  year      = {1990},
  language  = {en}
}
@article{HelsperMoelterKaminski1990,
  author    = {Helsper, Christoph and M{\"o}lter, W. and Kaminski, S.},
  title     = {Automatisierter Test von Luftfiltermedien f{\"u}r Hochleistungsschwebstoffilter und Entstaubungsfilter / M{\"o}lter, W. ; Helsper, C. ; Kaminski, S.},
  series = {Staub, Reinhaltung der Luft. 50 (1990)},
  journal   = {Staub, Reinhaltung der Luft. 50 (1990)},
  isbn      = {0039-0771},
  pages     = {311 -- 317},
  year      = {1990},
  language  = {de}
}