@incollection{HelsperFissanFranzen1978,
  author    = {Helsper, Christoph and Fissan, H. J. and Franzen, H.},
  title     = {Particle Size Distributions of Combustion Aerosols},
  series = {Atmospheric Pollution 1978 : Proceedings of the 13th International Colloquium; 25-28 April 1978; Paris, France; Edited by Michel M. Benarie},
  booktitle = {Atmospheric Pollution 1978 : Proceedings of the 13th International Colloquium; 25-28 April 1978; Paris, France; Edited by Michel M. Benarie},
  editor    = {Benarie, Michel M.},
  publisher = {Elsevier},
  address   = {Amsterdam},
  isbn      = {0-444-41691-9},
  doi       = {10.1016/S0166-1116(08)71583-8},
  pages     = {263 -- 266},
  year      = {1978},
  abstract  = {It has been observed that carcinogenic polycyclic aromatic hydrocarbons (PAH) are present in the atmosphere. Combustion processes are considered the most important sources for PAH. Among these, the burning of coal produces the highest emission, but in cities with high traffic density and low meteorological exchange activities, vehicle emissions determine the immission situation, especially in narrow streets. For estimating the potential health effects caused by PAH, it is sufficient to characterize the emission of PAH with respect to their physical state, concentrations, and, as far as the particulate phase is concerned, size distribution. The size distribution is important for transport phenomena, inhalation, and deposition in the respiratory tract. These parameters mainly depend on the combustion system, on system operating conditions, on the exhaust system, and on exhaust cooling conditions. At exhaust-gas temperatures in the range of ambient air temperatures, almost the whole emission of PAH is made up of particulate matter.},
  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{HelsperFissan1979,
  author    = {Helsper, Christoph and Fißan, H. J.},
  title     = {Numerical Simulation Studies and Data Reduction for Size Classifying Measurement Techniques / Fißan, H. J.; Helsper, C.},
  series = {Aerosols in science, medicine and technology : conference / Gesellschaft f{\"u}r Aerosolforschung 7. 1979.},
  journal   = {Aerosols in science, medicine and technology : conference / Gesellschaft f{\"u}r Aerosolforschung 7. 1979.},
  pages     = {199 -- 205},
  year      = {1979},
  language  = {en}
}
@article{HelsperFissan1980,
  author    = {Helsper, Christoph and Fißan, H. J.},
  title     = {Numerical Simulation Studies and Data Reduction for Size Classifying Measurement Techniques / Fißan, H. J.; Helsper, C.},
  series = {Advances in Particle Sampling and Measurement: Proceedings, Daytona Beach, EPA 600/9 80 004, 1980},
  journal   = {Advances in Particle Sampling and Measurement: Proceedings, Daytona Beach, EPA 600/9 80 004, 1980},
  publisher = {National Technical Information Service},
  address   = {Springfield, Va.},
  pages     = {VII, 409 S.},
  year      = {1980},
  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{HelsperFissan1981,
  author    = {Helsper, Christoph and Fißan, H. J.},
  title     = {Response Characteristic of a Polytec HC-15 Optical Particle Counter},
  series = {Aerosols in science, medicine and technology : Physical and chemical properties of aerosols : Association for Aerosol Research: annual conference. 1980 : Gesellschaft f{\"u}r Aerosolforschung: annual conference. 1980 : Aerosols in science, medicine and technology : Physical and chemical properties of aerosols : Associa-tion for Aerosol Research: annual conference. 1980 : Gesellschaft f{\"u}r Aerosolforschung: annual conference. 1980 : Schmallenberg, 22.10.80 - 24.10.80},
  journal   = {Aerosols in science, medicine and technology : Physical and chemical properties of aerosols : Association for Aerosol Research: annual conference. 1980 : Gesellschaft f{\"u}r Aerosolforschung: annual conference. 1980 : Aerosols in science, medicine and technology : Physical and chemical properties of aerosols : Associa-tion for Aerosol Research: annual conference. 1980 : Gesellschaft f{\"u}r Aerosolforschung: annual conference. 1980 : Schmallenberg, 22.10.80 - 24.10.80},
  publisher = {Pergamon Pr.},
  address   = {Oxford},
  pages     = {287 -- 292},
  year      = {1981},
  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{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{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{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{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{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{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{HelsperBartzFissanetal.1985,
  author    = {Helsper, Christoph and Bartz, H. and Fißan, H. J. and Kousaka, Y. (u.a.)},
  title     = {Response Characteristics for Four Condensation Nucleus Counters to Particles in the 3 to 50 nm Diameter Range / Bartz, H. ; Fißan, H. J. ; Helsper, C.; Kousaka, Y. ; Okuyama, K. ; Keady, R. Fruin, S. ; McMurry, P. H.; Pui, D. Y. H. ; Stolzenburg, M. R.},
  series = {Journal of Aerosol Science. 16 (1985), H. 5},
  journal   = {Journal of Aerosol Science. 16 (1985), H. 5},
  isbn      = {0021-8502},
  pages     = {443 -- 456},
  year      = {1985},
  language  = {en}
}
@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{HelsperWiedensohlerLuetkemeieretal.1986,
  author    = {Helsper, Christoph and Wiedensohler, A. and L{\"u}tkemeier, E. and Feldpausch, M.},
  title     = {Investigation on the Bipolar Charge Distribution at Various Gas Conditions / Wiedensohler, A.; L{\"u}tkemeier, E.; Feldpausch, M. ; Helsper, C.},
  series = {Journal of Aerosol Science. 17 (1986), H. 3},
  journal   = {Journal of Aerosol Science. 17 (1986), H. 3},
  isbn      = {0021-8502},
  pages     = {413 -- 416},
  year      = {1986},
  language  = {en}
}
@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}
}
@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{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{Helsper1986,
  author    = {Helsper, Christoph},
  title     = {Measurement Techniques For Ultrafine Particles},
  series = {Ultrafine aerosols. Properties and behaviour. Proceedings of the 1. International Workshop on Ultrafine Aerosols of the Sonderforschungsbereich 209 'Stoff- und Energietransport in Aerosolen' -'Mass and energy transfer in aerosols'-, held at the Univ. of Duisburg on Sept. 29, 1986},
  journal   = {Ultrafine aerosols. Properties and behaviour. Proceedings of the 1. International Workshop on Ultrafine Aerosols of the Sonderforschungsbereich 209 'Stoff- und Energietransport in Aerosolen' -'Mass and energy transfer in aerosols'-, held at the Univ. of Duisburg on Sept. 29, 1986},
  address   = {Duisburg},
  year      = {1986},
  language  = {en}
}