Google Scholar is a good resource for research papers. Search stuff like "link spam detection", etc.
Links are not equal. Don't fall in the trap of thinking many links is OK. Focus on quality. The harder a link is to get, the more valuable it is. And don't look for PR all the time. Sometimes a page that now is PR0 or PR n/a but is on a PR8 site that has a good internal linking structure, could one day become a PR5 page easily.