TY - JOUR JF - jsci JO - VL - 1368 IS - 3 PY - 1989 Y1 - 1989/7/01 TI - 8 TT - 8 N2 - 8 SP - 0 EP - 0 AD - KW - 8 UR - http://jsci.khu.ac.ir/article-1-1270-fa.html ER -