Table 1.
A summary of some of the digital libraries described in this Review.
Figure 1.
A mind map [207] summarizing the contents of this article in a convenient manner.
Figure 2.
The approximate relative coverage and size of selected digital libraries described in the section Digital Libraries, DOIs, and URIs, and summarised in Table 1.
Of all the libraries described, Google Scholar probably has the widest coverage. However, it is currently not clear exactly how much information Google indexes, what the criteria are for inclusion in the index, and whether it subsumes other digital libraries in the way shown in the figure. Note: the size of sets (circles) in this diagram is NOT proportional to their size, and DBLP, Scopus, and arXiv are shown as a single set for clarity rather than correctness.
Figure 3.
Google Scholar search results, identified by http://scholar.google.com/scholar?q = mygrid.
Google Scholar links out to external content using a number of methods including OpenURL [89], shown here by the “Find it via JRUL” (JRUL is a local library) links. Unlike, e.g., WoK, it is relatively easy to create inbound links to individual authors and publications in Google Scholar; see text for details.
Figure 4.
A typical workflow for using a digital library representing a subset of the literature.
Tasks represented by white nodes are normally performed exclusively by humans, while tasks shown in blue nodes can be performed wholly or partly by machines of some kind. The main problematic tasks that make digital libraries difficult to use for both machines and humans are “GET” (publication) and “GET METADATA”. These are shown in bold and discussed further in the Identity Crisis section of this paper.
Figure 5.
Mekentosj Papers can organize large collections of locally stored PDF files, with their metadata.
It looks and feels much like the popular iTunes application, allowing users to manage their digital libraries by categories shown at the top. It is presently available only under Mac OS/X.