In one sentence, describe what the following article is about:

Your referees, should they agree to be your referees, are doing you a favor. Give them at least two weeks to prepare and, if necessary, write you a letter of recommendation. There is some disagreement about the best way to ask someone to be a reference. Asking someone in person or over the phone is more personal, but you run the risk of making someone uncomfortable. Asking someone in an email is less personal, but it gives the person a chance to consider the request. Use your best judgment.  Whether you ask for a reference in person, on the phone, or in an email, give the potential referee the option of saying “no.” Ask the potential referee, “Do you feel that you are able to give me a strong reference?” If a potential referee does in fact say “no,” be grateful. It’s far better to have someone who really wants give you a reference on your side.  Be polite. Let your potential referees know how much you appreciate their efforts. And let them know that you’re available to answer any questions they might have. Supply them with job ad itself. You should also come up with your own description of the position. Remember the lists you made when you were deciding who to ask? Now’s the time to use those lists again. Make an effort to draw connections between your potential referee’s qualifications and the position for which you’re applying. For example, you might say, "Since you are a successful business owner, I thought that Business University's School of Business would value your opinion of me." Be very upfront about what you want your referees to say about you. You might say something along the following lines: “Given our history, I think you’re the right person to talk about my abilities in these areas…”  You can offer them anything from a simple list to a full-blown draft of a letter of recommendation. The more specific and thorough you are, the more grateful your referees will be. Give your referees explicit permission to add or delete parts of your guide as they see fit. This will let your referees know that you trust their judgement. You can say, “This is just a guide. I hope that you will make whatever changes you think are necessary.” Remember: an updated resume is far more useful than an out-of-date one. Once you’ve submitted your application materials, be sure to send thank-you notes, and keep your referees in-the-loop about the progress of your job search. A quick email that begins, “I wanted to give an update about the job I applied for.” Whether or not you end up getting the position for which you applied, maintaining contact with your referees is a smart idea. You might need to call on them to provide references for other applications. And they might be able to alert you to job openings.

Summary:
Ask early. Decide how you will ask. Tell your referees about the position. Explain why you’re asking them. Offer a guide. Give your referees a copy of your resume. Follow up.