Barnes & Noble Inc, the object of a proxy battle by billionaire investor Ronald Burkle, sent shareholders a letter urging them to vote for its board nominees and to reject a proposal from Burkle.

In the letter, sent Thursday, the book store chain said Burkle was seeking to gain control of the company without paying full value. It said his proposal to let investors buy upto 30 percent of the company's shares, instead of the current20 percent limit, was "self-serving."

Barnes & Noble said it believed Burkle, through his investment vehicle Yucaipa, would like the ability to form a control bloc with another Los Angeles-based investor, Aletheia Research & Management.

"Your board urges you to stop what we believe is Burkle's thinly veiled attempt to seize control of Barnes & Noble by supporting your board's three highly qualified nominees," the company said in its letter.

Yucaipa and Aletheia could not immediately be reached for comment.

Barnes & Noble highlighted the steps it has taken to build shareholder value, such as naming a new chief executive,launching a digital strategy and putting itself up for sale.

Burkle launched a proxy battle on Aug. 12 after losing a challenge to the company's "poison pill" and after talks with Leonard Riggio, the company's chairman and largest shareholder,broke down. Burkle is now seeking a seat on the company's board along with two other outside directors.

The company's annual shareholder meeting is scheduled for Sept. 28 in New York.

Barnes & Noble shares were up 17 cents, or 1.1 percent, at$15.54 in morning trade on the New York Stock Exchange. (Reporting by Martinne Geller, editing by Gerald E. McCormick and John Wallace)