Read this and answer the question

The Detroit Free Press and The Detroit News are the major daily newspapers, both broadsheet publications published together under a joint operating agreement called the Detroit Newspaper Partnership. Media philanthropy includes the Detroit Free Press high school journalism program and the Old Newsboys' Goodfellow Fund of Detroit. In March 2009, the two newspapers reduced home delivery to three days a week, print reduced newsstand issues of the papers on non-delivery days and focus resources on Internet-based news delivery. The Metro Times, founded in 1980, is a weekly publication, covering news, arts & entertainment.

Under which agreement are Detroit's major newspapers published?
Detroit Newspaper Partnership