Faizah, Restu, and Akhmad Aminullah. “Simple Laboratory Test to Measure Damping Properties of Hardened Mortar or Concrete Elements”. International Journal of Sustainable Construction Engineering and Technology, vol. 11, no. 1, May 2020, pp. 76-86, https://penerbit.uthm.edu.my/ojs/index.php/IJSCET/article/view/6229.