the incomplete contracting theory crucially rely on the specification of the negotiations protocol and on whether or not there is asymmetric information. Other models Efficiency wage models like that of Shapiro and Stiglitz (1984) suggest wage rents as an addition to monitoring, since this gives employees an incentive not to shirk, given a certain probability of detection and the consequence of being fired. Williamson, Wachter and Harris (1975) suggest promotion incentives within the firm as an alternative to morale-damaging monitoring, where promotion is based on objectively measurable performance. (The difference between these two approaches may be that the former is applicable to a blue-collar environment, the latter to a white-collar one). Leibenstein (1966) sees a firm's norms or conventions, dependent on its history of management initiatives, labour relations and other factors, as determining the firm's "culture" of effort, thus affecting the firm's productivity and hence size. George Akerlof (1982) develops a gift exchange model of reciprocity, in which employers offer wages unrelated to variations in output and above the market level, and workers have developed a concern for each other's welfare, such that all put in effort above the minimum required, but the more able workers are not rewarded for their extra productivity; again, size here depends not on rationality or efficiency but on social factors. In sum, the limit to the firm's size is given where costs rise to the point where the market can undertake some transactions more efficiently than the firm. Recently, Yochai Benkler further questioned the rigid distinction between firms and markets based on the increasing salience of “commons-based peer production” systems such as open source software (e.g., Linux), Wikipedia, Creative Commons, etc. He put forth this argument in The Wealth of Networks: How Social Production Transforms Markets and Freedom, which was released in 2006 under a Creative Commons share-alike license. Grossman–Hart–Moore theory In modern contract theory, the “theory of the firm” is often identified with the “property rights approach” that was developed by Sanford J. Grossman, Oliver D. Hart, and John H. Moore. The property rights approach to the theory of the firm is also known as the “Grossman–Hart–Moore theory”. In their seminal work, Grossman and Hart (1986), Hart and Moore (1990) and Hart (1995) developed the incomplete contracting paradigm. They argue that if contracts cannot specify what is to be done given every possible contingency, then property rights (and hence firm boundaries) matter. Specifically,