Information Processing Letters
Information Processing Letters > 2005 > 96 > 4 > 141-145
Information Processing Letters > 2007 > 102 > 4 > 147-151
Information Processing Letters > 2010 > 110 > 17 > 757-760
Information Processing Letters > 2005 > 96 > 4 > 141-145
Information Processing Letters > 2007 > 102 > 4 > 147-151
Information Processing Letters > 2010 > 110 > 17 > 757-760