(3GdCKHGJ GdLfGFj HGdbQGFf (B/s - (3YHO GdMGaX GdYHO GdgGOj YGHOs ((3GdbGgQI (B:s {(3Ohf OGQ fTQ(B}(3,s, 1989)
. 790-834 (3HHdjhLQGajG(B: (3UaMGJs
(3GdfU HGddZI GdYQHjIs
Keywords: (3GdbQGFfs; (3GdbGfhf GdLfGFjs