Less formal approaches to institutional complementarities have also been adopted. They are understood here as complementarities. Early on in this research, they focused on the importance of complementarities in organizational design. Hirschman called the industries with greatest complementarities as the 'leading sectors'. The complementarities of technologies and property rights create two different sets of organizational equilibria. Institutional complementarities characterize also the relations between intellectual property and human capital investments. Subsequently, Milgrom and Bengt Holmstrom (1994), used similar methods to identify complementarities in incentive design. In fact natural capital, social capital and economic capital are often complementarities.