A state judge ruled today that Boston University and the widow of the Rev. Dr. Martin Luther King Jr. must go to trial to determine who has lawful right to more than 83,000 documents that the slain civil rights leader left to the university in his lifetime.

His widow, Coretta Scott King, sued Boston University in 1987 demanding the return of the papers, which include about a third of all Dr. King's letters, manuscripts and other papers and form the centerpiece of the university's collection of personal archives. She said the papers belong with other archival material of Dr. King's at the King Center for Nonviolent Social Change, in Atlanta.

Boston University countersued, insisting it was the lawful owner of all Dr. King's papers, including those in Atlanta. The latter claim has since been dismissed by the courts, but the university has continued to assert that the papers it holds should not be taken to Atlanta. Dr. King earned his doctorate in theology from Boston University in 1955.

In today's ruling, Judge Herbert Abrams of Suffolk Superior Court rebuffed requests from lawyers for both Mrs. King and Boston University for a summary judgment, saying the case was too complex to settle out of court. He set a trial date of March 2 in Boston.