Sequoia Voting Systems has threatened possible legal action if a Princeton University professor independently analyzes the company's electronic voting machines for a New Jersey county.

Union County leaders requested a review after paper records showing the number of voters that cast ballots in each party didn't match the machine's printouts.

The company said this week that it will "vigorously protect and defend its intellectual property and enforcement of established licensing agreements." Sequoia released two statements explaining its stance on independent reviews of its e-voting machines after Princeton University professor Ed Felton received an e-mail warning him of legal action if he followed through with a request by New Jersey officials to examine Sequoia's e-voting machines.

The company said that it allows top-to-bottom reviews of e-voting machines within the framework of its license rights and according to arrangements between Sequoia and governmental agencies legally authorized to conduct reviews.

"Sequoia welcomes all such responsibly executed review activities," the company explained in a statement. "Sequoia does not support any and all unauthorized activities that violate or circumvent our product licensing agreements. Licensing agreements are standard practice in the technology industry, including the elections industry and have been for decades."

In addition to noting that the machines have passed federal and state certification tests, the company said it has commissioned Kwaidan Consulting of Houston to conduct an independent source code review of the software used to operate the Advantage e-voting equipment in New Jersey.

Sequoia said a report resulting from its current independent review will be sent to the New Jersey Attorney General's Office and Sequoia Voting Systems, which plans to post the report on its Web site.

Wyle Laboratories of Huntsville, accredited to test voting machines in Alabama, is also reviewing the updated source code to ensure that the reporting issue in New Jersey was corrected in an updated version of Sequoia's software. That test aims to satisfy requirements under New Jersey's Voting System Certification process.

For redundancy, Wyle Laboratories, another accredited testing lab, or academic researchers will also review New Jersey's software, Sequoia said.

The company had issued a product bulletin to customers and posted a blog explaining how the reporting issue in New Jersey happened, but the blog has been removed. Sequoia's offices were closed Friday afternoon, so representatives were not immediately available to provide the company's explanation. The day after the primaries, the company attributed voting problems in New Jersey to human error.