References = contact info for previous bosses, coworkers, professors etc. who can speak to your ability to do the job of whatever they are hiring for. NOT letters.

Please do NOT call and ask the prospective employer about what they mean. They will laugh and you will not be considered for the job.

References should be on a separate document (i.e. not at the bottom of your resume) and you typically be formatted as this:

Firstname Lastname
Title / Position, Company (not their current position and company, but what they were when you worked with them)
Office phone number
Mobile phone number
Email address