Information Processing Letters
Information Processing Letters > 1998 > 65 > 4 > 183-188
Information Processing Letters > 1998 > 68 > 6 > 295-298
Information Processing Letters > 2000 > 73 > 5-6 > 163-165
Information Processing Letters > 2000 > 76 > 3 > 113-119
Information Processing Letters > 2004 > 90 > 6 > 307-313
Information Processing Letters > 2005 > 94 > 2 > 93-97