Information Processing Letters
Information Processing Letters > 2004 > 92 > 6 > 275-277
Information Processing Letters > 2007 > 101 > 1 > 13-19
Information Processing Letters > 2013 > 113 > 18 > 685-689
Information Processing Letters > 2004 > 92 > 6 > 275-277
Information Processing Letters > 2007 > 101 > 1 > 13-19
Information Processing Letters > 2013 > 113 > 18 > 685-689