M. Conforti, R. Froio, G. Matteucci, T. Caloiero, and G. Buttafuoco, “Potentiality of laboratory visible and near infrared spectroscopy for determining clay content in forest soil: a case study from high forest beech (fagus sylvatica) in Calabria (southern Italy)”, EQA, vol. 11, no. 11, pp. 49–64, Jan. 2013.