[4-(5'-Trifluoromethylpyridyl-2'-oxy)-phenoxy]-propionic acid esters with .alpha.-hydroxy or .alpha.-mercapto gamma-butyrolactone and their use as herbicides

Granted: Jul 26, 1983 Filed: Jul 31, 1980

This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.