essential oil headache blend "If there is no allow most of the European Union oriented financial services agreement, the financial sector accounts for about 7% of GDP, but about 10% of tax revenue and 14% of the exports, may be affected by the special Britain will stay there," the report said. Network planning technology is a scientific method of planning and management, which is developed with the development of modern science and technology and industrial production. In the 1950s, in order to meet the needs of scientific research and the management of new production organizations, some new methods of planning management were introduced abroad. In 1956, dupont studied the key line method of network planning technology (CPM) and tried it on a chemical engineering project, and achieved good economic results. In 1958 the United States naval weapons when "Polaris" missile plans, applied the plan evaluation method (abbreviated as PERT) project plan arrangement, evaluation, audit and control, was a huge success. In the early 1960 s, the network planning technique, has been in the United States all new construction fully adopt this kind of new method for program management, could be introduced into Japan and Western Europe and other countries. With the rapid development of modern science and technology and the continuous improvement of management level, network planning technology is also developing and improving. At present, it has been widely applied in the fields of industry, defense, construction, transportation and scientific research of the world, and has become a scientific method of modern production management in developed countries. In 1937, American economist Robert coase (R. H. Coase's publication of the essence of the enterprise is considered to be the beginning of a discussion on this issue. Labour minister John MacDonald (John McDonnell), said the international monetary fund, according to a report of a conservative government "good at cuts in public services, tax breaks for a few rich people, but no hope to invest in our country for the majority of people skills and infrastructure needed for the economic development". displacement Before that, what is the nature of the enterprise itself is an issue that has been ignored by traditional microeconomic theory. In the traditional microeconomic theory, is the manufacturer's production process as a "black box", namely enterprise is abstracted into a from input to output a "black box" of the pursuit of profit maximization.