Zhu, Kaiguang, Chengquan Chi, Zining Yu, Weichen Zhang, Mengxuan Fan, Kaiyan Li, and Qiong Zhang. “Extracting Borehole Strain Precursors Associated With the Lushan Earthquake through Principal Component Analysis”. Annals of Geophysics 61, no. 4 (October 19, 2018): SE447. Accessed April 29, 2024. https://www.annalsofgeophysics.eu/index.php/annals/article/view/7633.