Google scholar uses h-index defined as
The h-index of a publication is the largest number h such that at least h articles in that publication were cited at least h times each. For example, a publication with five articles cited by, respectively, 17, 9, 6, 3, and 2, has the h-index of 3.
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import igraph as ig
import numpy as np
import matplotlib.pyplot as plt
from scipy import stats
from math import *
%load_ext autoreload
%autoreload 2
%matplotlib inline
    
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N = int(10)
M = 1
# uniform attachment
ua = ig.Graph.Growing_Random(n=N, m=M,
                             directed=True, citation=True)
    
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    Out[4]:
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g = ua.copy()
g.vs['indeg'] = g.indegree()
g.vs.select(_indegree_gt = 5)
    
    Out[10]:
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# subgraph of vertices who have indegree at least one
dsg = g.subgraph(g.vs.select(_indegree_ge=1))
# vertices who have at least one citer whose degree is at least one
dsg.vs.select(indeg_ge = 1)
    
    Out[26]:
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