Granted Patent
Utility
US 5,331,544 · App. 07/872,881
Market research method and system for collecting retail store and shopper market research data
Inventors:
Daozheng Lu, David A. Kiewit, Jia Zhang
Patented Case
View Patent ↗
Granted: Jul 19, 1994
Filed: Apr 23, 1992
Inventors
Daozheng Lu
David A. Kiewit
Jia Zhang
Assignee (at issue)
A.C. Nielsen Company
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.