2002.05.3-4 \I[O ` a b c d e f g h g[ig qhubN Ę ĂŞ§ ĂŞ§ Qn§ Qn§ Ţǧ Ţǧ xR§ xR§ Q ~ R-Q Q-R ~ R-Q Q-R ~ P-S S-P S ~ O-T T-O ~ Q-R R-Q R ~ Q-R R-Q P