Nothing like a proxy fight to get the emails racing and the blood boiling. Burkle, the L.A. billionaire who is trying to get three seats on the bookseller's board, told shareholders that Barnes & Noble management has diminished the company's value. He also insists that Yucaipa Cos., his investment arm, has "no hidden agenda to take control of the company." Then the Barnes & Noble folks released a 28-page footnoted "white paper" that accused Burkle of damaging the companies he has invested in over the years. There's also a section about Burkle's record on corporate boards, including locally based KB Home and Occidental Petroleum. B&N shareholders vote is Sept. 28.