Bibliometric Evidence for a Hierarchy of the Sciences
Bibliographic coupling networks, in Fruchterman-Reingold layout, with node size proportional to degree, and edge size and colour reflecting weight (i.e. number of shared references between any two papers: blue = 1; yellow = ≥2; red ≥5).
Numbers report average degree, modularity and average path length. Classification based on journal, following the systems of Essential Science Indicators and Arts & Humanities Science Citation Index: ma = mathematics; sp = Space Science; ph = Physics; ch = Chemistry; mb = Molecular Biology; bb = Biology & Biochemistry; pa = Plant and Animal Sciences; ee = Environment/Ecology; pp = Psychiatry/Psychology; eb = Economics & Business; so = Social Sciences, general; ah = Arts & Humanities. High-resolution images available from the authors. [Data sourced from Thomson Reuters Web of Knowledge].