1. Multimodal optimization of structures with frequency constraints
2. Das , S. K. , Ulku , S. , Chen , S. K. and Wada , B. K.A mathematical basis for the design optimization of adaptive trusses in 32nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Baltimore , MD , 829 – 839 ( 1991 ).