@article{HelsperFissanKapadietal.1982,
  author    = {Helsper, Christoph and Fißan, H. J. and Kapadi, A. and Liu, B. Y. H.},
  title     = {Data Inversion by Simplex Minimization for the Electrical Aerosol Analyzer},
  series = {Aerosol Science and Technology. 1 (1982), H. 1982},
  journal   = {Aerosol Science and Technology. 1 (1982), H. 1982},
  isbn      = {0278-6826},
  pages     = {136 -- 146},
  year      = {1982},
  language  = {en}
}
@article{HelsperFissanKasper1984,
  author    = {Helsper, Christoph and Fißan, H. J. and Kasper, W.},
  title     = {Kalibrierung der Partikelgr{\"o}ßenbestimmung von optischen Partikelz{\"a}hlern / Fißan, H. J.; Helsper, C. ; Kasper, W.},
  series = {3. Europ{\"a}isches Symposion Partikelmeßtechnik : [PARTEC, eine Veranstaltung der Reihe Partikel-Technologie N{\"u}rnberg ; N{\"u}rnberg, 9. - 11. Mai 1984 ; preprints] = 3. European Symposium on Particle Characterization / Veranst.: GVC, Gesellschaft Verfahrenstechnik und Chemieingenieurwesen im Verein Deutscher Ingenieure (VDI). Red. Bearb.: Kurt Leschonski},
  journal   = {3. Europ{\"a}isches Symposion Partikelmeßtechnik : [PARTEC, eine Veranstaltung der Reihe Partikel-Technologie N{\"u}rnberg ; N{\"u}rnberg, 9. - 11. Mai 1984 ; preprints] = 3. European Symposium on Particle Characterization / Veranst.: GVC, Gesellschaft Verfahrenstechnik und Chemieingenieurwesen im Verein Deutscher Ingenieure (VDI). Red. Bearb.: Kurt Leschonski},
  publisher = {NMA N{\"u}rnberger Messe- und Ausstellungsges.},
  address   = {N{\"u}rnberg},
  pages     = {263 -- 274},
  year      = {1984},
  language  = {de}
}
@article{HelsperFissanKasper1984,
  author    = {Helsper, Christoph and Fißan, H. J. and Kasper, W.},
  title     = {Calibration of Optical Particle Counters with Respect to Particle Size / Fißan, H. J. ; Helsper, C.; Kasper, W.},
  series = {Particle and Particle Systems Characterization. 1 (1984), H. 1984},
  journal   = {Particle and Particle Systems Characterization. 1 (1984), H. 1984},
  isbn      = {1521-4117},
  pages     = {108 -- 111},
  year      = {1984},
  language  = {en}
}
@article{HelsperFissanMugglietal.1980,
  author    = {Helsper, Christoph and Fißan, H. J. and Muggli, J. and Scheidweiler, A.},
  title     = {Particle Number Distributions of Aerosols from Test Fires},
  series = {Journal of Aerosol Science. 11 (1980), H. 5-6},
  journal   = {Journal of Aerosol Science. 11 (1980), H. 5-6},
  isbn      = {0021-8502},
  pages     = {439 -- 446},
  year      = {1980},
  language  = {en}
}
@article{HelsperFissanMugglietal.1983,
  author    = {Helsper, Christoph and Fißan, H. J. and Muggli, J. and Scheidweiler, A.},
  title     = {Verification of Ionization Chamber Theory},
  series = {Fire Technology. 19 (1983), H. 1},
  journal   = {Fire Technology. 19 (1983), H. 1},
  isbn      = {1572-8099},
  pages     = {14 -- 21},
  year      = {1983},
  language  = {en}
}
@article{HelsperFissanThielen1983,
  author    = {Helsper, Christoph and Fißan, H. J. and Thielen, H. J.},
  title     = {Determination of Particle Size Distributions by Means of an Electrostatic Classifier / Fißan, H. J.; Helsper, C. ; Thielen, H. J.},
  series = {Journal of Aerosol Science. 14 (1983), H. 3},
  journal   = {Journal of Aerosol Science. 14 (1983), H. 3},
  isbn      = {0021-8502},
  pages     = {354 -- 357},
  year      = {1983},
  language  = {en}
}
@book{HelsperFissanAhrens1979,
  author    = {Helsper, Christoph and Fißan, Heinz and Ahrens, Werner},
  title     = {Entwicklung eines Meßsystems zur direkten Bestimmung der Partikelgr{\"o}ßenverteilung von Aerosolen aus Verbrennungsvorg{\"a}ngen / Fißan, Heinz; Helsper, Christoph; Ahrens, Werner},
  publisher = {Westdeutscher Verl.},
  address   = {Opladen},
  isbn      = {3-531-02827-8},
  pages     = {47 S.: 14 graph. Darst.},
  year      = {1979},
  language  = {de}
}
@article{HelsperHornSchneideretal.2008,
  author    = {Helsper, Christoph and Horn, Hans-Georg and Schneider, Friedhelm and Wehner, Birgit},
  title     = {Intercomparison of five mobility size spectrometers for measuring atmospheric submicrometer aerosol particles / Helsper, Christoph ; Horn, Hans-Georg ; Schneider, Friedhelm ; Wehner, Birgit ; Wiedensohler, Alfred},
  series = {Gefahrstoffe, Reinhaltung der Luft. Air Quality Control. 68 (2008), H. 11-12},
  journal   = {Gefahrstoffe, Reinhaltung der Luft. Air Quality Control. 68 (2008), H. 11-12},
  isbn      = {0949-8036},
  pages     = {475 -- 481},
  year      = {2008},
  language  = {en}
}
@article{HelsperLuetkemeierWiedensohler1986,
  author    = {Helsper, Christoph and L{\"u}tkemeier, E. and Wiedensohler, A.},
  title     = {Charge Distribution by Unipolar Charging of Small Aerosol Particles / L{\"u}tkemeier, E. ; Helsper, C. ; Wiedensohler, A.},
  series = {Aerosols : formation and reactivity ; proceedings of the second International Aerosol Conference, 22-26 Sept. 1986, Berlin (West) / Gesellschaft f{\"u}r Aerosolforschung (GAeF) ; American Association for Aerosol Research (AAAR)},
  journal   = {Aerosols : formation and reactivity ; proceedings of the second International Aerosol Conference, 22-26 Sept. 1986, Berlin (West) / Gesellschaft f{\"u}r Aerosolforschung (GAeF) ; American Association for Aerosol Research (AAAR)},
  publisher = {Pergamon Press},
  address   = {Oxford [u.a.]},
  pages     = {474 -- 478},
  year      = {1986},
  language  = {en}
}
@article{HelsperMoelter1989,
  author    = {Helsper, Christoph and M{\"o}lter, L.},
  title     = {Erzeugung von Pr{\"u}faerosolen f{\"u}r die Kalibrierung von optischen Partikelmeßverfahren nach VDI 3491},
  series = {Technisches Messen. 56 (1989)},
  journal   = {Technisches Messen. 56 (1989)},
  isbn      = {0171-8096},
  pages     = {229 -- 234},
  year      = {1989},
  language  = {en}
}