Dynamic SQL in PL/SQL

Where and how I can get info. of using dynamic SQL in PL/SQL? BTW, I found that there are PL/SQL package dbms_sql which can execute dynamic SQL, which manuals mention those packageS???

Thanks,

--
**********************************************************************
Kam-ming Ku (kmku)	          Big-5:[ÅUÀA©ú]   GB: ~{9K=uCw~}	
Assistant Computer Officer	
Main Library,				Email : kmku_at_hkucc.hku.hk
The University of Hong Kong,		Tel.  : (852) 2859-8068  
Pokfulam Road, Hong Kong.               Fax.  : (852) 2858-9420
*********************************************************************