Kolodynskij, V. and Baltrėnas, P. 2017. Biogas production experimental research by using sewage sludge loading with biochar additive. Mokslas – Lietuvos ateitis / Science – Future of Lithuania. 9, 4 (Sep. 2017), 371-375. DOI:https://doi.org/10.3846/mla.2017.1062.