?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.au=Hamm%2C+Prof.+Dr.+Ulrich&rft.aulast=Hamm&rft.aufirst=Ulrich&rft.date=2006&rft.title=The+need+for+a+long-term+strategy+for+data+collection+on+organic+markets&rft.genre=proceeding