$1!^S!3x!Ky!5y!M"!2r!T2!I} (B/ s - $1'`v!F#!C(s ($1!T+!4I!<D (B: s $1!7o!_7K_p!<e!6F!CZ!04!U<!FM!7o!Qm!CZ!Q1!`D!BX!4H!0P!E-!C\!^v!3'!5-(B, s, 1992)