1. Zh. Iliev, „Comparative assessment of technological parameters of a conveyor belt and a cable -belt conveyor within an open pit mine“ (XIV International Conference of the open and underwater mining of minerals Varna Bulgaria), 2017, p 207
2. I. Iliev, „Economic damages caused by the low quality of the electrical energy”, Energien forum, Varna, 2017, pp. 50–55
3. N. Lakov, „Otkloneniya na naprezhenieto”, Energien forum, 2020, 37/38, pp. 42–46
4. R. Panchev, I. Iliev, G. Georgiev, and V. Chikov, „Study on influence of the quality of the electrical energy on the reliability of the electrical equipment and systems”, International scientific conference, 16-17 November 2018, Gabrovo, pp. 40–44
5. The voltage asymmetry in electrical networks with single-phase load