Chau, Dang, AND 		Cuong, Nguyen.
" On the asymptotic behavior of delay differential equations  a n d  i t s  r e l a t i o n s h i p  w i t h  Co- s e m i g r o u p" <em>VNU Journal of Science: Mathematics - Physics</em> [Online], Volume 23 Number 2 (15 June 2007)