2Warfield, J. N. , (1973a). On arranging elements of a hierarchy in graphic form[C]. IEEE Transactions on Systems, Man, and Cybernetics, SMC3 (2), 121-132.
3Warfield, J. N. , (1973b). Binary matrices in system modeling[C]. IEEE Transactions on Systems, Man, and Cybernetics, SMC3(2),133-140.
4Warfield, J. N. , (1974a). Toward Interpretation of Complex Structural Models[C].IEEE Transactions on Systems, Man, and Cybernetics, SMC4(5),405-417.