Information Processing Letters
Information Processing Letters > 2006 > 99 > 4 > 158-162
Information Processing Letters > 2008 > 105 > 4 > 131-137
Information Processing Letters > 2012 > 112 > 5 > 179-185
Information Processing Letters > 2006 > 99 > 4 > 158-162
Information Processing Letters > 2008 > 105 > 4 > 131-137
Information Processing Letters > 2012 > 112 > 5 > 179-185