%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 2014 %\ 06/01/2014 %V 40 %N 3 %P - %! Bulletin of the Iranian Mathematical Society %R %X %U http://bims.iranjournals.ir/article_532_8dd7670ec7eb6c5d19ad0ed9e3024589.pdf