It's just common sense. If you are going to claim that you have science supporting your position then it is common sense to cite the article written by the actual scientists who did the research. It just so happens that scientists publish these articles in peer reviewed journals which ensures the reader that other knowledgeable scientists have read over the article. Those peer scientists determine if the conclusions are consistent with the results and methodologies in the paper, and that the paper properly addresses the other research within that field.
Go to the peer reviewed sources and show that their conclusions are supported.
Show that they are in agreement.
No one is claiming that peer review guarantees an absolute lack of bias. Peer review is just the first hurdle that any scientific findings must cross. If you disagree with the conclusions in a peer reviewed article then cite that article, and explain why you disagree. This gives us some insurance that you are familiar with the material and can discuss it with us.
When you cite material from creationist sites all you see is the conclusions made by the author of the article at the creationist site, and then quote it if it agrees with your own opinions. Chances are, you have no idea how the sources they are referencing support their arguments, or if they do at all. We are here to discuss these topics with YOU, so it is you that needs to be prepared to discuss your position. That is why we ask that you use the peer reviewed papers that contain the actual science.