(CNN) When legendary singer Aretha Franklin died, she did not have a will or trust. Her four sons have filed a document listing themselves as interested parties, reports say. Franklin died last week from advanced pancreatic cancer. She was 76. Aretha Franklin funeral set for August 31 in Detroit In addition to her sons' filing, Franklin's niece has asked the court to appoint her as a personal representative of the estate, the Detroit Free Press reported. It said under Michiga