Volume 34, Issue 2, April 2017, Pages 581-598
A. M. Okasha; M. A. Helmy; A. W. Zaghlol
Volume 27, Issue 4, October 2010, Pages 1674-1687
M. Helmy; T. Fouda; A. Derbala; O. Kaddour; N . Yassa
Volume 26, Issue 3, July 2009, Pages 1397-1411
M. Helmy; A. Derbala; S. Badr; S. Shohyieb