Figure 2.

Two small lexica and their PubAtlas result, when run in the context “PubMed”[TIAB]. The first is a list of systems that extend the PubMed interface, and the second is a list of some characteristic features. The table shown is the PubAtlas output summarizing results of all pairs of queries x AND y, where x is a system and y is a feature, omitting rows and columns having no intersection. For this is simple pair of lexica, with no pretense of completeness, the resulting machine-generated table can serve as an interactive review paper - an overview of publications about these systems. The table is also a web-based interface that spawns interactions with PubMed.