#
#  collect all  <process> <used> <artifact> relationships
#

PREFIX    a:  <http://www.ipaw.info/2007/opm#>
PREFIX    b:  <http://taverna.opm.org/>
PREFIX rdfs:  <http://www.w3.org/2000/01/rdf-schema#>
PREFIX  rdf:  <http://www.w3.org/1999/02/22-rdf-syntax-ns#>

SELECT ?artifact ?value
		
WHERE
{ 
      ?artifact  rdf:type a:Artifact .
      OPTIONAL {  ?artifact b:value ?value }
 }