1. Pure and applied mathematics;RA Adams,2003
2. Aldenderfer, M. S., & Blashfield, R. K. (1984). Cluster analysis. Beverly Hills: Sage.
3. Anderberg, M. R. (1973). Cluster analysis for applications. New York: Academic.
4. Arabie, P., & Lawrence, J. H. (1994). Cluster analysis in marketing research. In R. P. Bagozzi (Ed.), Advanced methods of marketing research (pp. 160–189). Cambridge, MA: Blackwell.
5. Arabie, P., & Lawrence, J. H. (1996). An overview of combinatorial data analysis. Clustering and classification (pp. 5–63). Singapore: World Scientific.