HAERI, HADI, PHD CANDIDATE OF ROCK MECHANICS, DEPARTMENT OF MINING ENGINEERING, SCIENCE AND RESEARCH BRANCH, ISLAMIC AZAD UNIVERSITY, TEHRAN, IRAN
HAFED, ZAHRA S., DEPARTMENT OF MATHEMATICS, FACULTY OF SCIENCE, KAFRELSHEIKH UNIVERSITY, KAFRELSHEIKH 33516, EGYPT / DEPARTMENT OF MATHEMATICS, FACULTY OF SCIENCE, KING KHALED UNIVERSITY, ABHA 21589, SAUDI ARABIA