BOSTON – Norman Rockwell’s three sons are among the plaintiffs who have filed a court complaint seeking to halt a Massachusetts museum’s plans to sell 40 works of art, including two by their father.

The complaint filed Friday alleges the Berkshire Museum in Pittsfield contracted with Sotheby’s for a public auction of the works before it announced its plans publicly. The complaints say it acted in breach of its fiduciary duties and trust, and without legal authority to sell the art.

The museum says the sale is necessary to maintain its long-term financial viability as it refocuses its mission on science and history. Proceeds will be used for an endowment and renovations.

A Berkshire spokeswoman said the museum believes it has “strong legal grounds” for the sale.