<｜begin▁of▁sentence｜>### Instruction:
Given a graph representing academic papers, where each node is a paper and the edges represent citations, how would you calculate the bibliographic coupling scores for a subset of papers (nodes 1, 2, and 3)?
### Response:
from igraph import Graph

# Assuming we have a graph with papers as nodes and citations as edges
documents_graph = Graph.Read_GML('documents.gml')

# Calculate bibliographic coupling scores for vertices 1, 2 and 3
bibcoupling_scores = documents_graph.bibcoupling(vertices=[1, 2, 3])

# Print the resulting matrix
print(bibcoupling_scores)
<|EOT|>
