. . "Forum Math. Sigma" . . "1010677950" . . . . . "2012" . "Forum of Mathematics, Pi and Sigma" . . . . "Forum of Mathematics, Sigma" . "Forum of Mathematics" . "Forum of Mathematics, Pi" . "Forum of Mathematics" . . "847482162" . . . . . "2050-5094" . . . . . . "Forum Math. Pi" . "Open(gold)" . "2050-5086" .