The Division of Marketing & Communications uses the Associated Press Stylebook as a guide for journalistic copy. If you are writing a news release about the university, let AP be your guide.
For more formal, literary or academic writing, the Chicago Manual of Style is standard.
These guidelines are intended to help achieve consistency, but style can always change with usage or context. These rules are not set in concrete. They may be adapted—or even ignored—when necessary for clarity, accuracy and precision.