1. Technical University of Gabrovo,Department of Machine and Precision Engineering,Gabrovo,Bulgaria
2. Technical University of Gabrovo,Department of Mechanical Engineering Technology and Machine Tools,Gabrovo,Bulgaria
3. Instruments Technical University of Sofia,Department of Precision Engineering and Measurement,Sofia,Bulgaria
4. Ukrainian Engineering Pedagogics Academy,Department of Information Computer Technologies and Mathematics,Kharkiv,Ukraine
5. Technical University of Sofia,Department of Automation of Discrete Production Engineering,Sofia,Bulgaria
6. Academician Emil Djakov Institute of Electronics,Bulgarian Academy of Sciences,Sofia,Bulgaria