@book{HufnagelKuehn2009,
  author    = {Hufnagel, W. and K{\"u}hn, R.},
  title     = {Betriebliches Rechnungswesen, Externes Rechnungswesen, LE 1-4},
  address   = {Hagen},
  year      = {2009},
  language  = {mul}
}