@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}
}
@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}
}
@article{HelsperMoelter1987,
  author    = {Helsper, Christoph and M{\"o}lter, W.},
  title     = {Determination and Neutralization of the Charge Produced by the Dispersion of Powders},
  series = {Journal of Aerosol Science. 18 (1987), H. 6},
  journal   = {Journal of Aerosol Science. 18 (1987), H. 6},
  isbn      = {0021-8502},
  pages     = {877 -- 880},
  year      = {1987},
  language  = {de}
}
@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}
}
@article{HelsperWiedensohlerWeiseetal.1986,
  author    = {Helsper, Christoph and Wiedensohler, A. and Weise, W. and L{\"u}tkemeier, E.},
  title     = {Determination of the Bipolar Charge Equilibrium in Pure Gases / Wiedensohler, A. ; Weise, W. ; Helsper, C. ; L{\"u}tkemeier, E.},
  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     = {383 -- 386},
  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}
}
@article{Helsper1979,
  author    = {Helsper, Christoph},
  title     = {Evaluation of Particle Size Distributions by Means of Particle Counters / Fißan, H. J. ; Helsper, C.},
  series = {Proceedings of the First Workshop of Particulate Control : 16. - 17. March 1978, Kernforschung-sanlage J{\"u}lich GmbH / prepared by U.S. Environmental Protection Agency, Off. of Research and Development, Washington, D.C, 1979,},
  journal   = {Proceedings of the First Workshop of Particulate Control : 16. - 17. March 1978, Kernforschung-sanlage J{\"u}lich GmbH / prepared by U.S. Environmental Protection Agency, Off. of Research and Development, Washington, D.C, 1979,},
  publisher = {Zentralbibliothek d. Kernforschungsanlage J{\"u}lich [in Komm.]},
  address   = {J{\"u}lich},
  pages     = {495 S.: Ill., graph. Darst.},
  year      = {1979},
  language  = {en}
}
@article{HelsperMoelterKaminski1989,
  author    = {Helsper, Christoph and M{\"o}lter, W. and Kaminski, S.},
  title     = {Fast and Automated Testing of Different Air Filter Media / M{\"o}lter, W. ; Helsper, C. ; Kaminski, S.},
  series = {1. Europ{\"a}isches Symposium Partikelabscheidung aus Gasen : [PARTEC, N{\"u}rnberg, West Germany, 19. - 21. April 1989 ; preprints] = 1. European Symposium Separation of Particles from Gases / [Organisation und Durchf{\"u}hrung: N{\"u}rnbergMesse]. Hrsg. von: Friedrich L{\"o}ffler},
  journal   = {1. Europ{\"a}isches Symposium Partikelabscheidung aus Gasen : [PARTEC, N{\"u}rnberg, West Germany, 19. - 21. April 1989 ; preprints] = 1. European Symposium Separation of Particles from Gases / [Organisation und Durchf{\"u}hrung: N{\"u}rnbergMesse]. Hrsg. von: Friedrich L{\"o}ffler},
  publisher = {N{\"u}rnbergMesse},
  address   = {N{\"u}rnberg},
  pages     = {441 -- 457},
  year      = {1989},
  language  = {en}
}
@article{HelsperMoelterKaminski1989,
  author    = {Helsper, Christoph and M{\"o}lter, W. and Kaminski, S.},
  title     = {Fast and Automated Testing of Different Air Filter Media / M{\"o}lter, W. ; Helsper, C. ; Kaminski, S.},
  series = {Proceedings of the Filtech Conference, Karlsruhe 1989, Vol. 1},
  journal   = {Proceedings of the Filtech Conference, Karlsruhe 1989, Vol. 1},
  publisher = {Filtration Society},
  address   = {Oadby},
  pages     = {125 -- 136},
  year      = {1989},
  language  = {en}
}
@article{HelsperMoelterWillemer1987,
  author    = {Helsper, Christoph and M{\"o}lter, W. and Willemer, W.},
  title     = {Fast and Automated Testing of Filter Media / M{\"o}lter, W. ; Helsper, C. ; Willemer, W.},
  series = {FILTECH Conference 1987 : Utrecht, Holland; September 23 - 25 1987 / org. by the Filtration Society , Vol. 1.},
  journal   = {FILTECH Conference 1987 : Utrecht, Holland; September 23 - 25 1987 / org. by the Filtration Society , Vol. 1.},
  publisher = {Filtration Society},
  address   = {Loughborough},
  pages     = {106 -- 112},
  year      = {1987},
  language  = {en}
}
@article{HelsperMoelterKaminski1992,
  author    = {Helsper, Christoph and M{\"o}lter, W. and Kaminski, S.},
  title     = {Fast, Automated Testing of Different Air Filter Media / M{\"o}lter, W. ; Helsper, C. ; Kaminski, S.},
  series = {Filtration and Separation. 29 (1992), H. 1},
  journal   = {Filtration and Separation. 29 (1992), H. 1},
  isbn      = {0015-1882},
  pages     = {45 -- 50},
  year      = {1992},
  language  = {en}
}
@article{Helsper1993,
  author    = {Helsper, Christoph},
  title     = {Integrit{\"a}tspr{\"u}fung an LF-Anlagen mit Hilfe von Pr{\"u}faerosolen},
  series = {Pharma-Technologie-Journal. 14 (1993), H. 2},
  journal   = {Pharma-Technologie-Journal. 14 (1993), H. 2},
  isbn      = {0931-9700},
  pages     = {36 -- 42},
  year      = {1993},
  language  = {de}
}
@article{HelsperDreilingHalleretal.1986,
  author    = {Helsper, Christoph and Dreiling, V. and Haller, P. and Kaminski, U.},
  title     = {Intercomparison of Eleven Condensation Nucleus Counters / Dreiling, V. ; Haller, P. ; Helsper, C.; Kaminski, U. ; Plomp, A. ; Raes, F. ; Roth, C. ; Schier, J. ; Sch{\"u}rmann, G.},
  series = {Journal of Aerosol Science. 17 (1986), H. 3},
  journal   = {Journal of Aerosol Science. 17 (1986), H. 3},
  isbn      = {0021-8502},
  pages     = {565 -- 570},
  year      = {1986},
  language  = {en}
}