TY - JOUR JF - jsci JO - VL - 1371 IS - 4 PY - 1991 Y1 - 1991/1/01 TI - 4 TT - 4 N2 - 4 SP - 0 EP - 0 AD - KW - 4 UR - http://jsci.khu.ac.ir/article-1-1274-fa.html ER -