Figure 2

ST corresponding to a PDF paper from the Virology Journal identified by PubMed ID 18234069. Documents are organized hierarchically. The root node <root, null, null> represents the entire document. Complex sections (e.g. containing multiple subsections) are hierarchically decomposed according to the original paper structure. For instance, the section <abstract, "Abstract", null> can be decomposed into its three child sections: <subAbstract, "Background", "Dengue is...">, <subAbstract, "Results", "An optimal..."> and <subAbstract, "Conclusion", "These findings...">. Nodes of types table(e.g. <table, "Table 2: Comparison of...", "M-RT-PCR\tVirus isolation\nPositive\t96 (15.48%)\t...">) and figure(e.g. <figure, "Figure 1", "1.5% Agarose gel electrophoresis...">) are considered as special sections and thus allocated as children of the root node—the escape sequences "\t" and "\n" denote tab and newline characters. The natural reading order of the PDF paper can be reproduced by iterating the ST in depth-first order.