1. Ma, T.H., Spinrad, J.P.: Cycle-tree partial orders and chordal comparability graphs. Order 8(1), 49–61 (1991)
2. Breiman, L., Friedman, J., Olshen, R., Stone, C.: Classification and Regression Trees. Wadsworth, Belmont, CA (1984)
3. Stanley, R.P.: Enumerative Combinatorics, vol. 1, p. 335. Cambridge University Press, Cambridge (1997)
4. Mesarović, M., Mako, D., Takahara, Y.: Theory of Hierarchical Multilevel Systems, p. 294. Academic Press, New York (1970)
5. Saaty, T.L.: The Analytic Hierarchy Process: Planning, Priority Setting, p. 287. Resource Allocation. McGraw-Hill, New York (1980)