$1!4\'b^!0d(B. $1'18!@9'<v'\9!WD'44s - $1'a,!63!Th!=u(B. $1'V*!3^!9]s ($1!X4!B@'[4!3K!JH!Nas, 1990)
Keywords: $1!_t!G=!5FK7o!BX':`s