I need information on the Death Penalty?

I have to write a persuasive research paper on why the Death Penalty is a good thing. I need three sources, and I'm NOT allowed to use Wikipedia. I have two sources so far: deathpenaltyinfo.org and aclu.org. The site has to be similar to those (FACTS. IT CANNOT BE A SITE THAT IS ONE SIDED). Any help would be appreciated, please and thank you! =)