Figure 3. Bibliographic coupling network of papers, partitioned by scientific domain (total N = 28,477; yellow  =  mathematics; blue  =  physical sciences; darker green  =  biological-hard sc.; lighter green  =  biological-soft sc.; red  =  social sc.; purple  =  humanities).

Panel A: probabilities to share a given number of references with any other paper in the sample, estimated by exponential random graph modelling. The model controlled for number of references cited by each paper, number of triangles and edges. Error bars are 95% Confidence Intervals, bh is the reference category, and has therefore all values set to zero. Panel B: network of shared references, in Yifan Hu Proportional layout. Panel C: network partitioned by domain, with average degree, modularity and average path length. [Data sourced from Thomson Reuters Web of Knowledge].