1. dr Milko Yovchev (2023) "MEASUREMENT AND ANALYSIS OF THE SPECTRAL EMISSION OF DIFFERENT TYPES OF DOMESTIC LAMPS IN THE BLUE LIGHT HAZARD WAVELENGTH RANGE" - Contemporary Materials 2023 - Savremeni materijali
(https://ekonferencije.com/hr/rad/measurement-and-analysis-of-th/6508)

2. dr Milko Yovchev (2019) "Technical and Economic Development of the Photovoltaic Electricity in Bulgaria" - Contemporary Materials 2019 - Savremeni Materijali
(https://ekonferencije.com/hr/rad/technical-and-economic-develop/5723)