In the past decades the role of the State has undergone major alterations regarding supply of goods and services in general, particularly housing supply. There is a clear trend towards less direct intervention of the public agents in the supply process, encouraging participation of non-public agents, such as the private sector, NGO's (non-governmental organisations, with a volunteer character), and communities that receive goods and services -- in this case, housing. This is certainly a global trend encompassing both industrially advanced and developing countries. The mechanism of supplying...