Don't use the back of a page. If you need to go to a second page for your references, go to page 2. Also, in the future try to keep your resume to a max of two pages...a little bit of spill over to a page 3 in a pinch. As your career progresses, you will briefly mention the earlier parts of your career, but the most recent stuff you can go into more detail (a "what have you done lately" type of thing).