%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 2016 %\ 12/18/2016 %V 42 %N 6 %P - %! Bulletin of the Iranian Mathematical Society %R %X %U http://bims.iranjournals.ir/article_892_76367872db19dee6e35769d297c7cbaf.pdf