Kaķītis, A., and I. Nulle. “Durability of Biomass Briquettes”.
ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June 26, 2006): 139–144. Accessed April 16, 2025.
https://journals23.rta.lv/index.php/ETR/article/view/1999.