Article rights.

If I hire someone to write articles for me, how can I get the proof that he has given me full rights to the article ? Can i like make a small webpage with a place to post his article and under the submit button i write a sentence saying. 'By pressing the submit button you are agreeing to giving me full rights to the article beeing submitted'. Can i do it like that ?

even if you did put a button making them say so, they could sell it again if they wanted. chances are your not going to take the guy to court for something so little because it takes too much time and money.

just buy from buyers who have a high feedback. you can find some good ones at DP of GAF

What about getafreelancer and those kind of sites ?