Mashkov, Petko, Edmunds Teirumnieks, Berkant Gyoch, Hristo Beloev, Tamara Pencheva, and Rostislav Kandilarov. 2015. “Design of LED Lamp With Special Spectral Characteristics”. ENVIRONMENT. TECHNOLOGIES. RESOURCES. Proceedings of the International Scientific and Practical Conference 1 (June): 147-52. https://doi.org/10.17770/etr2015vol1.214.