Credibility

Since Stanford University’s Persuasive Technology Lab conducted its research on web credibility over six years ago, countless writers have referred to its pioneering, and still mostly relevant, insight into how users judge organizations based on their websites.

Is it “my boss’s dirty laundry” or “my boss’ dirty laundry”? Should it be “an historian” or “a historian”?

If other people will be reading what you’re writing, a style guide may be the best place to check.