UMI Dissertation Publishing [ProQuest] <http://www.proquest.com/>

University of Chicago Press <http://www.press.uchicago.edu/>

USDA Agricultural Research Service <http://www.ars.usda.gov/>

USDA Forest Service  <http://www.fs.fed.us/>

Vigne & Vin - Publications Internationales <http://www.vigne-vin.com/vvpi/>

VINITI (All-Russian Scientific and Technical Information Institute of Russian Academy of Sciences <http://www.viniti.ru/>

VITIS-VEA  <http://www.vitis-vea.de/>

Wageningen Universiteit <http://www.wur.nl/uk/>

Water Environment Federation <http://www.wef.org>

Weed Science Society of America <http://www.wssa.net>

Wiley  <http://eu.wiley.com/>

Wiley OnLine Library  <http://onlinelibrary.wiley.com/>

Wiley-VCH <http://www.wiley-vch.de/>

WorldWideScience.org <http://worldwidescience.org/>

WWW Virtual Library  <http://vlib.org/>

ultimo aggiornamento: 12/04/2011