Methods, systems, and apparatus, including computer programs encoded on computer storage media, for associating resources based on resource associations. One of the methods includes receiving a first profile, wherein the first profile is for a first author, wherein the first profile links to one or more first documents, wherein the first author is an author of each of the one or more first documents; identifying, one or more second authors, wherein each of the one or more second authors is a co-author of one or more of the first documents; calculating, respective co-author scores for each of the one or more second authors; ranking, the one or more second authors based on their respective co-author scores; and associating, the one or more second authors with the first profile, the first profile includes a listing of the one or more second authors in an order according to the ranking.