Toloue, I., M. S. Liew, I. S. H. Harahap, and H. E. Lee. “A Novel Algorithm for Effective Vibration Control of Portal Frames”. Journal of Engineering and Technological Sciences, vol. 50, no. 3, Aug. 2018, pp. 315-29, doi:10.5614/j.eng.technol.sci.2018.50.3.1.