Vahdani, B. , Tavakkoli-Moghaddam, R. , Baboli, A. , Mousavi, S. (2013). 'A New Fuzzy Mathematical Model in Recycling Collection Networks: A Possibilistic Approach'. World Academy of Science, Engineering and Technology, Open Science Index 78, International Journal of Industrial and Manufacturing Engineering, 7(6), 1252 - 1260.