An article in a journal written by two professors is your best choice. The second option is a no go because how would you know if the website was using credible evidence or an author who knew what they were talking about? A personal blog is a no go as well because they would have no concrete evidence other than what they know, also a student report on plagiarism in college isn't a solid choice either because then it's second hand evidence and you don't know whether they have credible sources. Hope this helps!