Heirs of American author John Steinbeck say they’re being cut out of negotiations – over possible movie deals – involving the late Nobel Prize-winning writer’s books.

The author’s surviving son, Thomas Steinbeck, and the wife of another son, Nancy Steinbeck, filed a petition this month with the California Labor Commission.

Among the claims are that the RSWG Literary Agency and agent Geoffrey Sanford were negotiating Hollywood deals without consulting Steinbeck’s heirs.

It’s the latest chapter in a lengthy legal wrangle over control of Steinbeck’s works.

The agency’s lawyer has said that Thomas Steinbeck and Nancy Steinbeck gave up control over Steinbeck’s works as part of a 1983 legal settlement.