AktG says the same for the management board, while under §111 AktG the supervisory board's role is stated to be to "oversee" (überwachen). In the United Kingdom, the right to manage is not laid down in law, but is found in Part.2 of the Model Articles. This means it is a default rule, which companies can opt out of (s.20 CA 2006) by reserving powers to members, although companies rarely do. UK law specifically reserves shareholders right and duty to approve "substantial non cash asset transactions" (s.190 CA 2006), which means those over 10% of company value, with a minimum of £5,000 and a maximum of £100,000. Similar rules, though much less stringent, exist in §271 DGCL and through case law in Germany under the so-called Holzmüller-Doktrin. Probably the most fundamental guarantee that directors will act in the members' interests is that they can easily be sacked. During the Great Depression, two Harvard scholars, Adolf Berle and Gardiner Means wrote The Modern Corporation and Private Property, an attack on American law which failed to hold directors to account, and linked the growing power and autonomy of directors to the economic crisis. In the UK, the right of members to remove directors by a simple majority is assured under s.168 CA 2006 Moreover, Art.21 of the Model Articles requires a third of the board to put themselves up for re-election every year (in effect creating maximum three year terms). 10% of shareholders can demand a meeting any time, and 5% can if it has been a year since the last one (s.303 CA 2006). In Germany, where employee participation creates the need for greater boardroom stability, §84(3) AktG states that management board directors can only be removed by the supervisory board for an important reason (ein wichtiger Grund) though this can include a vote of no-confidence by the shareholders. Terms last for five years, unless 75% of shareholders vote otherwise. §122 AktG lets 10% of shareholders demand a meeting. In the US, Delaware lets directors enjoy considerable autonomy. §141(k) DGCL states that directors can be removed without any cause, unless the board is "classified", meaning that directors only come up for re-appointment on different years. If the board is classified, then directors cannot be removed unless there is gross misconduct. Director's autonomy from shareholders is seen further in §216 DGCL, which allows for plurality voting and §211(d) which states shareholder meetings