[4] Clairotte M, Grinand C, Kouakoua E, et al. Geoderma, 2016, 276: 41.
[5] Wei H, Li H, Liu P, et al. Spectroscopy Letters, 2017, 48(9): 470.
[6] Chakraborty S, Weindorf D C, Deb S, et al. Geoderma, 2017, 289: 72.
[8] Li X, Xie C, He Y, et al. Sensors, 2012, 12(7): 9847.
[11] Huang N E, Shen Z, Long S R, et al. Proceedings Mathematical Physical & Engineering Sciences, 1998, 454(1971): 903.
[14] Peterson L. Scholarpedia, 2009, 4(2): 1883.