List of Articles برنامهریزی ریاضی مثبت Open Access Article Abstract Page Full-Text 1 - Investigating the Economic and Welfare Effects of the Water Market: A Positive Mathematical Programming Model Approach fatemeh esmaelnia balagatabi ahmad sarlak hadi ghaffari Open Access Article Abstract Page Full-Text 2 - Change from the purchasing price policy to the guaranteed price policy and its effects on cropping pattern in Qazvin plain mehdi shabanzadeh Gholamreza peykanei seyed safdar hoseini saeid yazdanei