@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}
}
@article{HelsperNiessnerRoenicke1984,
  author    = {Helsper, Christoph and Nießner, R. and R{\"o}nicke, G.},
  title     = {Application of a Multistep Condensation Nuclei Counter as a Detector for Particle Surface Composition / Nießner, R.; Helsper, C.; R{\"o}nicke, G.},
  series = {Aerosols : science, technology, and industr. applications of airborne particles ; proceedings of the 1. Internat. Aerosol Conference held Sept. 17-21, 1984, Minneapolis, Minn., U.S.A / ed.: Benjamin Y. H. Liu},
  journal   = {Aerosols : science, technology, and industr. applications of airborne particles ; proceedings of the 1. Internat. Aerosol Conference held Sept. 17-21, 1984, Minneapolis, Minn., U.S.A / ed.: Benjamin Y. H. Liu},
  publisher = {Elsevier},
  address   = {New York [u.a.]},
  isbn      = {0444009477},
  pages     = {63 -- 66},
  year      = {1984},
  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}
}
@article{HelsperFissanFranzen1976,
  author    = {Helsper, Christoph and Fißan, H. J. and Franzen, H.},
  title     = {Bestimmung der Gr{\"o}ßenverteilung von Aerosolen aus Verbrennungsvorg{\"a}ngen mit einem elektrostatischen Aerosolanalysator},
  series = {Aerosole in Naturwissenschaft, Medizin und Technik : Bericht der Tagung der Gesellschaft f{\"u}r Aerosolforschung e.V. 4, 1976},
  journal   = {Aerosole in Naturwissenschaft, Medizin und Technik : Bericht der Tagung der Gesellschaft f{\"u}r Aerosolforschung e.V. 4, 1976},
  pages     = {118 -- 126},
  year      = {1976},
  language  = {de}
}
@book{Helsper1981,
  author    = {Helsper, Christoph},
  title     = {Bestimmung, Simulation und Korrektur des nichtidealen {\"U}bertragungsverhaltens klassifizierender Aerosolmeßverfahren},
  publisher = {Univ.-Gesamthochsch},
  address   = {Duisburg},
  pages     = {65 S.},
  year      = {1981},
  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{HelsperFissan1983,
  author    = {Helsper, Christoph and Fißan, H. J.},
  title     = {Calibration of the Polytec HC-15 and HC-70 Optical Particle Counters / Fißan, H. J. ; Helsper, C.},
  series = {Aerosols in the mining and industrial work environments, Vol. 3. Instrumentation, Marple, Virgil A. ; Liu, Benjamin Y.},
  journal   = {Aerosols in the mining and industrial work environments, Vol. 3. Instrumentation, Marple, Virgil A. ; Liu, Benjamin Y.},
  publisher = {Ann Arbor Science},
  address   = {Ann Arbor, Mich.},
  pages     = {825 -- 829},
  year      = {1983},
  language  = {en}
}
@article{HelsperMoelter1991,
  author    = {Helsper, Christoph and M{\"o}lter, W.},
  title     = {Characteristics of a Nebulizer with Cyclone Preseparator / M{\"o}lter, W. ; Helsper, C.},
  series = {Aerosols, their generation, behaviour and applications. Annual Conference of the Aerosol Society / Aerosol Society (UK) ; 5.},
  journal   = {Aerosols, their generation, behaviour and applications. Annual Conference of the Aerosol Society / Aerosol Society (UK) ; 5.},
  address   = {Loughborough},
  pages     = {89 -- 94},
  year      = {1991},
  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{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}
}