PITTSFIELD, Mass. -- The sons of famed artist Norman Rockwell are seeking to block the sale of their father's artwork from a museum in Pittsfield.

Rockwell's three sons are among the plaintiffs who filed a court complaint aimed at stopping the Berkshire Museum's plans to sell 40 works of art including, two by their father.

A complaint filed Friday seeks a temporary restraining order and alleges the museum in Pittsfield does not have the legal authority to sell the artwork.

Berkshire Museum officials say the sale is necessary to remain open as proceeds would go towards an endowment and renovations.