@article {MATHEDUC.02404746,
    author       = {Michelsen, U.A. and Hofferbert, B. and Mueller, J.},
    title        = {The consideration of partial solutions in calculating the degrees of test-item-difficulties. Die Beruecksichtigung von Teilloesungen bei der Berechnung des Schwierigkeitsgrades von Pruefungsaufgaben.},
    year         = {1991},
    journal      = {Zeitschrift f\"ur P\"adagogische Psychologie},
    volume       = {5},
    number       = {1},
    issn         = {1010-0652},
    pages        = {57-68},
    publisher    = {Huber, Bern},
    msc2010      = {M74xx (K94xx C80xx)},
    identifier   = {1992f.00210},
}