Ziemelis, I., U. Iljins, P. Savcenko, I. Zemļanojs, and I. Iļičovs. 1999. “SIVĒNU APSTAROŠANA AR ULTRAVIOLETAJIEM STARIEM”.
ENVIRONMENT. TECHNOLOGY. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June): 247-55.
https://doi.org/10.17770/etr1999vol1.1865.