The bibliographic reference and citations which exist among documents in a given document collection can be used to study the history and scope of particular subject areas and to assess the importance of individual authors, documents, and journals. A clustering study of computer science literature is described, using bibliographic citations as a clustering criterion, and conclusions are drawn regarding the scope of computer science and the characteristics of individual documents in the area. In particular, the clustering characteristics lead to a distinction between core and fringe areas in the field and to the identification of particularly influential articles.