1. Freitas, J.A.T. and D.L. Smith: A general methodology for nonlinear structural analysis by mathematical programming, Eng. Struct., 6, 1984
2. Freitas, J.A.T.: Elastic-plastic analysis of structural cross-sections, Mathematical Programming Methods in Structural Plasticity, CISM, Udine 1986
3. Freitas, J.A.T.: Elastic-plastic analysis of skeletal structures, Mathematical Programming Methods in Structural Plasticity, CISM, Udine 1986
4. Freitas, J.A.T. and D.L. Smith: Exact, dual description of equilibrium and compatibility for space frames, CTE 45, CMEST, 1982
5. Freitas, J.A.T. and D.L. Smith: Elastoplastic analysis of planar structures for large displacements, J. Struct. Mech., 12, 1984