Extracting a Bibliography Into Structured Citation Records

The instinct is to hand the whole reference list to a model and ask for an array of citation objects. On a list of eighty entries that produces seventy-three, with two merged and five hallucinated into tidiness. The fix is to make segmentation a separate, deterministic step. Two stages, and why the first one is harder Parsing one reference string into author, year, title and venue is a task current models do well. Deciding where one reference ends and the next begins is a task they do badly, because the boundary is typographic rather than semantic: a hanging indent, a numeric label, a line break that is either a wrap or a separator depending on the column width. Splitting the work also gives you a count to assert against. If the list is numbered 1 to 84 and you segmented 81 entries, you know the parse is wrong before you have looked at a single field. A single-call extraction gives you no such handle — a merged pair looks identical to a list that was three shorter. Step 1: segment the list Three reference-list styles cover almost everything, and each has a different boundary signal: Numbered (Vancouver, IEEE). Each entry begins with 1. or [1] . Boundary detection is a regex, the sequence is monotonic, and you get the assertion for free. Author-date (APA, Harvard, Chicago author-date). No labels. Entries are separated by a hanging indent — the first line starts at the margin and continuations are indented — which is invisible in a flat text stream and obvious in the layout. Note-bibliography (Chicago notes). Also unlabelled, also hanging-indented, and additionally uses a three-em dash for a repeated first author, which is the case discussed below. For the unlabelled styles, segment on the indent rather than on the text. If you have coordinates from the PDF, an entry starts at every line whose left edge is at the block minimum and continues through every line indented further. If you do not have coordinates, a reasonable proxy is a line that begins with a capital lett