Do your stated referees know they are your referees? Did you ask them before naming them?
What will your referees say about you? Are you absolutely certain they will say what you think they will say?
Google your name and clean up your social media, employers are using it like a ‘referee’ to check up on you.
Let your referees know the requirements of the job you are applying for, so they can speak of you in those terms.
Email addresses for referees are commonly asked for on application forms, follow through and list them on your resume as well.
When your referee is asked that all important question, ‘would you re-employ (insert your name)’, will he/she answer yes without hesitation? If you have any doubts, re-think your choices.