Ziemelis, Imants, Arnolds Šķēle, Henriks Putāns, Uldis Iljins, and Aldis Putāns. 2001. “VOLTAGE REGULATORS FOR LOCAL HEATING OF PIGLETS”. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June): 229-35. https://doi.org/10.17770/etr2001vol1.1967.