In Upjohn Co. v. United States (1981), the U.S. Supreme Court discussed the scope of the attorney-client privilege in the context of corporations. The Court reasoned that privileged communications are those made by corporate employees to corporate counsel on orders of superiors for the corporation to secure legal advice. Other criteria set by the Court are the the information sought and communicated concerned matters within the scope of the employees' corporate duties, that the employees were aware that the communications with counsel were ordered so that the corporation could obtain legal advice, and that the communications were ordered to be confidential and remained confidential. Considering these criteria, privileged communications are best promoted by having counsel direct all investigations related to the case. Also, the client should specifically request legal advice. Employees interviewed in a legal investigation should be informed to treat the matter as confidential both within the corporation and with outsiders, and documents claimed as privileged should be clearly designated to establish confidentiality. Clients should also be instructed not to communicate legal opinions and advice to anyone outside the company without specific authorization of counsel. Courts often hold that the disclosure of one privileged communication or document waives the privilege as to other communications on the same subject. Some common situations in which courts have found the privilege waived are client's use of confidential materials to refresh recollection, inadvertent production of privileged material, disclosure to a government agency, and injecting advice of counsel as an issue in litigation.