@book{HummelKochSkiera2009,
  author    = {Sebastian Hummel and Wolfram Koch and Bernd Skiera},
  title     = {E-Business-Konzepte f{\"u}r den Mittelstand},
  isbn      = {3-936598-45-2},
  url       = {http://www.marketing.uni-frankfurt.de/fileadmin/Publikationen/Skiera__Hummel_ebusiness-konzepte.pdf},
  year      = {2009},
}