Information Processing Letters
Information Processing Letters > 1995 > 53 > 1 > 49-54
Information Processing Letters > 1995 > 55 > 3 > 167-170
Information Processing Letters > 1995 > 56 > 3 > 131-133
Information Processing Letters > 1997 > 62 > 5 > 251-254
Information Processing Letters > 2007 > 104 > 5 > 179-182