Graph Nodes:
X1;X2;X4;X5;X6;X7;X8;X10;X12;X13

Graph Edges:
1. X1 o-> X13
2. X1 o-> X6
3. X10 o-> X13
4. X12 <-> X13
5. X2 o-> X13
6. X2 o-> X6
7. X4 o-> X12
8. X5 o-> X13
9. X6 --> X10
10. X6 <-> X12
11. X6 o-> X13
12. X7 o-> X13
13. X7 o-o X4
14. X8 o-> X13

