question concerning collections

In the SKOS core guide I do find following example :

<rdf:RDF
  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns:skos="http://www.w3.org/2004/02/skos/core#"
  xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#">
  
  <skos:Concept rdf:about="http://www.example.com/concepts#milk">
    <skos:prefLabel>milk</skos:prefLabel>
    <skos:narrower>
      <skos:Collection>
        <rdfs:label>milk by source animal</rdfs:label>
        <skos:member rdf:resource="http://www.example.com/concepts#buffalomilk"/>
        <skos:member rdf:resource="http://www.example.com/concepts#cowmilk"/>
        <skos:member rdf:resource="http://www.example.com/concepts#goatmilk"/>
        <skos:member rdf:resource="http://www.example.com/concepts#sheepmilk"/>
      </skos:Collection>
    </skos:narrower>
  </skos:Concept>
</rdf:RDF>

Where in this case Collection is within the narrower element as a blank node.

I suppose I can do the same using a node with a URI as follows.

<rdf:RDF
  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
  xmlns:skos="http://www.w3.org/2004/02/skos/core#"
  xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#">
  
  <skos:Concept rdf:about="http://www.example.com/concepts#milk">
    <skos:prefLabel>milk</skos:prefLabel>
    <skos:narrower rdf:resource="http://www.example.com/collections#milkbyanimal"/>
  </skos:Concept>
  
  <skos:Collection rdf:about="http://www.example.com/collections#milkbyanimal">
        <rdfs:label>milk by source animal</rdfs:label>
        <skos:member rdf:resource="http://www.example.com/concepts#buffalomilk"/>
        <skos:member rdf:resource="http://www.example.com/concepts#cowmilk"/>
        <skos:member rdf:resource="http://www.example.com/concepts#goatmilk"/>
        <skos:member rdf:resource="http://www.example.com/concepts#sheepmilk"/>
 </skos:Collection>

</rdf:RDF>


I just want to check since someone told me this can and may not be done according to the SKOS spec.

Regards,


Paul