Figure 6. Referencing behavior for authors of different recent collaboration level in five disciplines (astronomy (AST), mathematics (MAT), robotics (ROB), ecology (ECL), and economics (ECN)).

Authors with no collaborators are shown at collaboration level 1, those with one at x = 2, etc. A) Number of references per page (reference rate). B) Average age of references. C) Modified Price Index (fraction of references published within five years compared to those published within 10 years). D) Re-citation fraction (repeated citations in pairs of articles). Data are binned in intervals of 0.1 decades. Bins with fewer than four elements are excluded.