Granted Patent
Utility
US 4,876,357 · App. 07/113,840
Chromogenic phthalides and azaphthalides
Inventors:
Rox Phaff, Davor Bedekovic
Patented Case
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Granted: Oct 24, 1989
Filed: Oct 26, 1987
Inventors
Rox Phaff
Davor Bedekovic
Assignee (at issue)
Ciba-Geigy
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.