Hikari Ltd, P.O. Box 85
Rousse 7000, Bulgaria
Hikari Ltd, Rui planina str. 4, ent.7, fl.5
Rousse 7005, Bulgaria
E. Minchev holds master's degree in physics from Sofia University and Ph.D degree in mathematics from Chiba University, Japan. He has specialized in mathematical sciences in Waseda University, Tokyo, Japan.
Plamena Yordanova graduated from Ruse University, Bulgaria with master's degree in engineering sciences.