$1!04!7o!3x!1?!Og!Xf(B16 : s 80$1!T)(B90$1!<e!0s (B/ s - $1!O,!JTs; $1!:l!EXs; $1!To!Tys ($1!T+!4I!<D (B: s $1!2r!=o!CU!;P(B, s, 1993)