Rosle, Nurshahirah, and Ahmad Fahmy Kamarudin. 2021. “Effects of Vertical Irregularity (Upper Level) of 5-Storey Laboratory Steel Tower Using Modal Analysis”. Recent Trends in Civil Engineering and Built Environment 2 (1): 350-61. https://penerbit.uthm.edu.my/periodicals/index.php/rtcebe/article/view/1463.