Information Processing Letters
Information Processing Letters > 2001 > 77 > 2-4 > 123-129
Information Processing Letters > 2001 > 77 > 2-4 > 131-135
Information Processing Letters > 2001 > 77 > 2-4 > 209-212
Information Processing Letters > 2001 > 77 > 2-4 > 173-179
Information Processing Letters > 2001 > 79 > 2 > 57-63