Analysis of information sources in references of the Wikipedia article "科赫家族" in Chinese language version.
[W]hen he tried to market his invention, the major oil companies sued him for patent infringement. Koch eventually won the lawsuits (after 15 years in court), but the controversy made it tough [?!] to attract many US customers.
[W]hen he tried to market his invention, the major oil companies sued him for patent infringement. Koch eventually won the lawsuits (after 15 years in court), but the controversy made it tough [?!] to attract many US customers.