Look in the User Guide documentation for the appserver at the section named Resource References panel. It describes there how to setup the ref's. I found it really worth doing as well as I obtained over a 50 % performance increase for our application. Here is a piece of our DTD showing a resource reference

 
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	ejb/KarVPAVInventory
	Entity
	KarVPAVInventoryHome
	KarVPAVInventory
	KarVPAVInventoryBean
      .....