@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
@base <http://example.com/base/> .

<Target/PK=1010> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <Target> .
<Target/PK=1010> <Target#PK> 1010 .
<Target/PK=1010> <Target#key1attr1> "K1A11" .
<Target/PK=1010> <Target#key1attr2> "K1A21" .
<Target/PK=1010> <Target#key2attr1> "K2A11" .
<Target/PK=1010> <Target#key2attr2> "K2A21" .

<Target/PK=1011> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <Target> .
<Target/PK=1011> <Target#PK> 1011 .
<Target/PK=1011> <Target#key1attr1> "K1A12" .
<Target/PK=1011> <Target#key1attr2> "K1A22" .
<Target/PK=1011> <Target#key2attr2> "K2A22" .

<Source/ID=1100> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <Source> .
<Source/ID=1100> <Source#ID> 1100 .
<Source/ID=1100> <Source#attrA> "K2A21" .
<Source/ID=1100> <Source#attrB> "K2A11" .
<Source/ID=1100> <Source#ref-attrA;attrB> <Target/PK=1010> .

<Source/ID=1101> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <Source> .
<Source/ID=1101> <Source#ID> 1101 .
<Source/ID=1101> <Source#attrA> "K2A22" .