Stockl, A. (2013) “Near-infrared-reflection spectroscopy as measuring method to determine the state of the process for automatic control of anaerobic digestion”, International Journal of Agricultural and Biological Engineering, 6(2), pp. 63–72. Available at: https://www.ijabe.migration.pkpps06.publicknowledgeproject.org/index.php/ijabe/article/view/732 (Accessed: 27 February 2026).