A. I. EL-MAGHRABI 1, M. CALDAS 2, S. JAFARI 3, R. M. LATIF 4, A. NASEF 5, N. RA-JESH 6 AND S. SHANTHI 7 1. Departament of Mathematics, Faculty of Science, Taibah University P. O. Box, 30002, code, 41477, Al-Madinah Al-Munawarah, K. S. A.
e-mail: amaghrabi@taibahu.edu.sa
2. Departamento de Matematica Aplicada, Universidade Federal Fluminense, Rua Mario Santos Braga, S/n, 24020-140, Niteroi, RJ BRASIL
e-mail: gmamccs@vm.u_.br
3. College of Vestsjaelland South, Herrestraede, 11, 4200 Slagelse, DENMARK
e-mail: jafaripersia@gmail.com
4. Departament of Mathematics and Natural Sciences, Prince Mohammad bin Fahd University, P. O. Box 1664 Al Khobar, K. S. A.
e-mail: rlatif@pmu.edu.sa
5. Departament of Physics and Engineering Mathematics, Faculty of Engineering,
Kafrelsheikh University, Kafr El-sheikh 33516, EGYPT.
e-mail: nasefa50@yahoo.com
6. Department of Mathematics, Rajah Serfoji Govt. College, Thanjavur-613005, Tamilnadu, INDIA.
e-mail: nrajesh topology@yahoo.co.in
7. Department of Mathematics, Arignar Anna Govt. Arts College, Namakkel -637 001, Tamilnadu, INDIA.
e-mail: shanthiwini2005@yahoo.co.in