Information Processing Letters
Information Processing Letters > 1997 > 61 > 4 > 205-208
Information Processing Letters > 1997 > 64 > 3 > 143-147
Information Processing Letters > 1997 > 64 > 6 > 299-303
Information Processing Letters > 1998 > 67 > 3 > 151-156
Information Processing Letters > 2012 > 112 > 24 > 963-968