NEW YORK - Rihanna sued her former accountants Thursday, blaming them for tens of millions of dollars in losses, shoddy bookkeeping, a failure to recommend she trim expenses when a 2009 tour was losing money and an ongoing audit by the Internal Revenue Service. The lawsuit in federal court in Manhattan sought unspecified damages against New York-based Berdon LLP and two accountants. A Berdon spokeswoman said the company had no immediate comment. The singer, suing under her real name, Robyn Fenty, alleged through her attorneys that the defendants drained tens of millions of dollars from revenues while she launched four national and international tours over a five-year period. By the "Last Girl on Earth" tour in 2009, Rihanna learned that the tour had managed "significant net losses" despite robust revenues, though the defendants had managed to pocket 22 percent of the tour's total revenues.