%0 Journal Article %T Bulletin of the Iranian Mathematical Society %J Bulletin of the Iranian Mathematical Society %I Iranian Mathematical Society (IMS) %Z 1017-060X %D 2017 %\ 10/01/2017 %V 43 %N 5 %P - %! Bulletin of the Iranian Mathematical Society %R %X %U http://bims.iranjournals.ir/article_1182_5ac9306f6f518d1cfe3b1d5c6017a997.pdf