According to tarbell what practices had rockefeller used to establish standard oil company
Ida Tarbell, a journalist who authored the book The History of Standard Oil exposed that Standard Oil has violated the Sherman Anti-trust Act(competition law) which led to Rockefeller Oil company break-up. According to her investigative journalism, Rockefeller has been practicing illegal, unfair and immoral business strategies.
Standard Oil controls the docks and railroads so independent dealers cannot ship oil.