List of Articles Preference Open Access Article Abstract Page Full-Text 1 - Assessing the value efficiency of each unit in relation to the tangent hyper plane in DEA (units including negative data with interval scale) Hossein Abbasiyan Seyyed Ali Kazemipour Open Access Article Abstract Page Full-Text 2 - Developing a Model to Analyze Decision Maker's Preference in Portfolio Selection Sina Shirtavani Mahdi Homayoonfar Keihan Azadi Amir Daneshvar