http://example.org/x4 0 A1 http://example.org/x3 0 A http://example.org/x3 1 B http://example.org/x3 2 C http://example.org/x2 0 a http://example.org/x2 1 b http://example.org/x2 2 c http://example.org/x1 0 a http://example.org/x1 1 b http://example.org/x1 2 c