While there are technical caveats, we can briefly consider the implications of Figs . The PMID capture in Fig. shows a pattern of intersects and differences that is to some extent reflected for the other entities also. Each indicates some unique capture but ChEMBL and BindingDB overlap for ~25K papers. Despite being the smallest of the three, GtoPdb shows proportionally more unique PMIDs. This is dues to the curators adding additional references into the SID records beyond those from which the binding data were extracted (e.g. in vivo and clinical reports published after the initial in vitro results). Notably, the public total from all four of ~75K is less than 50% of the journal document counts declared by the two commercial sources (Table ). While the more limited resources of the public sector are clearly a factor it would be informative to know explicitly what was behind the differences. Journal selectivity is likely to be dominant but other factors may come into play.