Escalating the online bookselling wars, Amazon.com Inc. yesterday asked a federal judge to allow it to refer to the New York Times bestseller list in advertisements and on its World Wide Web site.

The request comes as the major online bookstores, including Amazon.com, rush to offer 50 percent discounts on titles appearing on the New York Times list, a widely watched barometer of the hottest books in the country. On Monday, lawyers at the newspaper sent Amazon.com and Borders.com a letter ordering the companies to stop referring to the bestseller list on their sites, calling it an unfair use of the company's property.

Experts view the move as an effort to bolster barnesandnoble.com, Amazon.com's rival, which has a deal with the New York Times to sell books through links on the newspaper's Web site. In addition, barnesandnoble.com pays a license fee to the New York Times in return for the right to refer to the newspaper's list. Terms of the deal are not public.

Amazon officials said yesterday that they had discussed the matter with the New York Times, and had revised the list by rearranging the books in alphabetic order rather than sales rank. But the talks broke down. Worried about a lawsuit, Amazon decided to strike first, asking late Thursday for a declaratory judgment in U.S. District Court in Seattle, where the company is based.

"The New York Times didn't want to work things out, so we reluctantly have gone to court," said Bill Curry, a company spokesman. "We want the courts to rule that we're making a fair use of facts."

In a statement yesterday, the New York Times said that Amazon.com is "using our property for its own commercial purposes and takes freely what other retailers license." Company officials also noted that Amazon.com is scooping the newspaper by publishing the list four days before the newspaper.

Intellectual property attorneys said yesterday that the New York Times is on shaky legal ground. Courts concluded years ago that a company can't claim copyright protections for lists of information simply because compiling the list took time and effort.

Attorneys said a trademark claim would be a stronger one for the New York Times, but still risky, particularly because Amazon.com is conveying the list accurately. Under the "fair use" doctrine, typically even trademarked material can be cited as long as the information isn't misleading.

"I've got Microsoft software on my computer and it's perfectly legal for me to say so," said Steve Englund, a partner at Arnold & Porter in Washington.

Complicating matters for the newspaper, bookstores and books themselves commonly cite the list in displays and promotions. Amazon.com and some lawyers say that referring to a book as a New York Times bestseller is like referring to an actor as an Academy Award winner.

"Even the New York Times publishes Academy Award winners and I doubt the paper has a license agreement with the Academy to do so," said Paul Kilmer, a partner at Gadsby & Hannah in Washington.

Officials at Borders.com said the company had no plans to remove references to the bestseller list from its Web site. "This is a surprise to us," said spokesman Rich Fahle, who added that Borders was not mentioned in the Times's cease and desist letter.