$1!C!!9(!0-!L,!M"'?n!L5!DU!;P(B: $1'3#'E&!DU!;P'Q0'Q4!0='=es - $1#?,'Hm!B}s ($1!04!1W!3K!JH!Nas, 1991)
Keywords: $1K7o'_7'Q+'Qqs