?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.aufirst=T+S&rft.au=Walker%2C+T+S&rft.aulast=Walker&rft.date=1985&rft.title=The+Economics+of+Deep+Vertisols+Technology+Options%3A+Implications+for+Design%2C+Testing%2C+and+Transfer+&rft.genre=proceeding