A group of economists and lawyers, who are largely linked to the University of Chicago, support a competitive law approach that is guided by the argument that certain measures, originally considered anti-competitive, could indeed promote competition.  The U.S. Supreme Court recently used Chicago`s school approach.  A view of the Chicago school`s approach to cartels and abuse of dominance can be found in the books Antitrust Law and Economic Analysis of Law of the United States Circuit Court of Appeals.  These restrictive agreements do not need to be formally written – they may even take the form of oral agreements. For example, if two employees of competing companies exchange information about the market and different competitors, this can be done through an oral transaction and information that is not written. They remain governed by competition law. The Sherman Act of 1890 attempted to prohibit restrictions on competition by large companies that worked with competitors to secure production, prices and market share, first through pools and then by trusts. Trusts appeared in U.S. railways, where the capital requirements of railway construction excluded competitive services in sparsely populated areas of the time. This confidence has allowed the railways to discriminate against the tariffs and services imposed on consumers and businesses and to destroy their potential competitors. Different trusts could dominate in different sectors. The Standard Oil Company`s confidence in the 1880s controlled several markets, including fuel oil, lead and whisky.
 Many citizens have been sufficiently aware and publicly concerned about how trusts have had a negative impact on them, namely that the law has become a priority for both major parties. One of the main concerns of this law is that competitive markets themselves should ensure primary regulation of prices, outputs, interest and profits. Instead, the law prohibited anti-competitive practices and codified general business practices.  Professor Rudolph Peritz argued that competition law has developed in the United States around two sometimes contradictory concepts of competition: first, that of individual freedom, free from state intervention, and second, a fair competitive environment without excessive economic power. Since the passage of the Sherman Act, the application of competition law has been based on various economic theories of government.  Europe changed rapidly around the 16th century.