Hyun Choi, Seung, et al. “A Preliminary Study on the New Geotechnical Weathering Index in the Evaluation of Altered Biotite Granite”. International Journal of Engineering & Technology, vol. 7, no. 2.23, Apr. 2018, pp. 91-98, https://doi.org/10.14419/ijet.v7i2.23.11891.