The Religious Technology Center maintains strict control over the use of Scientology symbols, icons, and names. It claims copyright and trademark over the "Scientology cross," and its lawyers have threatened lawsuits against individuals and organizations who have published these protected images without permission in books and on websites. Because of this, it is difficult for individual groups to attempt to practice Scientology publicly without any affiliation or connection to the "official" Church of Scientology. Scientology has sued a number of individuals who attempted to set up their own "auditing" practices, using copyright and trademark law to shut these competitors down.