To identify prior-art before the year 1996 that invalidates the subject patent. There were multiple claim limitations specifying to the design of sampling machine.
There were about 100 citations and already known arts that we need to bypass to achieve the prior-art. We performed multiple strategies and were not been able to identify any patent prior-art.
We shifted our focus to non-patent literature to countries with maximum usage of cotton and sampling machines. From, there by applying all strategies using our vast experience we were able to identify one non-patent literature that proved the ultimate prior-art to invalidate the subject patent.