4f4fc817_ATTLIST_Declaration__Tokenized_Attribute_Type_
[Attribute Description:] IDREF is used to establish connections between elements. The IDREF value of the attribute must refer to an ID value declared elsewhere in the document. The first character of an ID value must be a letter, '_', or ':'. See example. [Tokenized Attribute Type:] 
IDREF
I D
I D R E F
I D R E F S
E N T I T Y
E N T I T I E S
N M T O K E N
N M T O K E N S
ATTLIST Declaration
Tokenized Attribute Type: