1. A response spectrum method for random vibrations;Der Kiureghian,1980
2. Combination of modal responses;Gupta,1981
3. Combination of modal responses: a follow up, Rep.;Gupta,1982
4. A simple method of combining modal responses;Gupta,1983
5. Comparison of modal combination methods;Gupta;Nucl. Eng. Des.,1984