Guichen Ma, Kazuhide Sawada, Hideki Saito, Fumiaki Uehan, and Atsushi Yashima. 2012. “Study on Evaluating Rock Block Stability by Using a Remotely Positioned Laser Doppler Vibrometer”. GEOMATE Journal 2 (4):247-52. https://geomatejournal.com/geomate/article/view/1458.