About one -
First, the ATTLIST's syntax is wrong in the two options.
The specification says -
Well-formedness constraint: No External Entity References
Attribute values cannot contain direct or indirect entity references to external entities.
Well-formedness constraint: Parsed Entity
An entity reference must not contain the name of an unparsed entity. Unparsed entities may be referred to only in attribute values declared to be of type ENTITY or ENTITIES.
I think the fist constraint refers to external parsed entities when speaking about external entities.
Unparsed entity, in the second constraint, must mean 'external unparsed entity'.
So, an attribute can refer to an external unparsed entity in the following way -
The DTD will have -
<!ATTLIST myelement myattribute ENTITY #IMPLIED>
<!ENTITY e SYSTEM "...e.gif" NOTATION ..>
In the XML instance -
<myelement myattribute="e"/>
I hope it helps,
Dan
[ October 12, 2002: Message edited by: Dan Drillich ]