Quantitative analysis of pH value in soil using laser-induced breakdown spectroscopy coupled with a multivariate regression method Lu, Cuiping ; Lv, Gang ; Shi, Chaoyi ; Qiu, Duoyang ; Jin, Feixiang ; Gu, Man ; Sha, Wen Abstract Publication: Applied Optics Pub Date: October 2020 DOI: 10.1364/AO.401405 Bibcode: 2020ApOpt..59.8582L