Information Processing Letters
Information Processing Letters > 1995 > 54 > 5 > 249-251
Information Processing Letters > 1995 > 55 > 2 > 71-74
Information Processing Letters > 1997 > 63 > 5 > 277-282
Information Processing Letters > 1995 > 54 > 5 > 249-251
Information Processing Letters > 1995 > 55 > 2 > 71-74
Information Processing Letters > 1997 > 63 > 5 > 277-282