Mehdi Toloo, B.Sc. (Pure Mathematics), M.Sc. (Applied Mathematics/Operations Research), Ph.D. (Operations Research). Professor in the Department of Mathematics at the Azad University of Central Tehran Branch, Iran. Areas of interest include Network Flows, Multi-objective programming and Data Envelopment Analysis. He has written ten books. His research has been published in International Journal of Management Science, Computers & Operations Research, European Journal of Operational Research, International Journal of Production Research, Computers & Industrial Engineering, Applied Mathematics and Computers, Applied Mathematical Modelling, Expert Systems with Applications, and International Journal of Advanced Manufacturing Technology.