6 sources needed for research paper

Hi, I’ve written my research paper about prison reform. I’ve already added two sources from the internet. I need 6 more. I have to have a total of 8 sources but only 3 types of sources. It can be 3 articles, 3 journal entries, 3 books, 3 interviews, etc. But I need 6 more to complete my paper. Also, the 6 sources has to be documented properly in my paper and on my works cited page MLA format.  Can someone help?