Information Processing Letters
Information Processing Letters > 2004 > 90 > 2 > 81-86
Information Processing Letters > 2005 > 93 > 4 > 199-206
Information Processing Letters > 2006 > 97 > 4 > 153-155
Information Processing Letters > 2007 > 104 > 5 > 179-182
Information Processing Letters > 2011 > 111 > 11 > 503-507
Information Processing Letters > 2011 > 111 > 16 > 792-797