@misc{BuchholzGraweLuehrmann2015,
  author    = {Buchholz, Wolfgang and Grawe, Thomas and L{\"u}hrmann, Matthias},
  title     = {How to apply buyer-supplier-supplier relationships for defining sourcing strategies. 24th Annual International Purchasing and Supply Education and Research Association (IPSERA) Conference: "Preparing for new competitive challenges". Amsterdam, Netherlands. 29. March -1. April 2015},
  year      = {2015},
  language  = {en}
}