Volume 21.2, Issue 42, May 1989, Pages 24-27
Z. MOHAMED; S.M. HAFEZ
Volume 21.2, Issue 42, May 1989, Pages 28-33
M.S. WASSEL; K. ZAKI; A.Y. MOHSEN; EL.M. SAYED; A. EL-DEBDGY; Z. MOHAMED; M.M. TAHA