In a letter included in its regulatory filing, Barnes & Noble’s board has rejected the request of investor Ron Burkle to remove its poison pill provision and allow him acquire up to 37% of the national bookstore chain. In January Burkle sent a letter to the B&N board requesting the removal of the poison pill provision which was added by the B&N board in November 2009. Burkle owns 18.7% of B&N stock through his investment firm Yucaipa. The poison pill provision is triggered if a shareholder owning more than 20% of B&N stock acquires additional shares.