Citation extraction en

Skill matematicsolutions/awesome-matematic-skills-en/verification-foundation/skills/citation-extraction-en

English hub of method-neutral legal AI skills (verification core, content quality, EU law) - bundle model. Polish-jurisdiction skills live in awesome-matematic-skills-pl.

Install

npx -y skills add matematicsolutions/awesome-matematic-skills-en --skill citation-extraction-en

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What its author says it does

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Deterministically extracts every legal citation from an English-language text - ECLI (CJEU and national), EU act identifiers (CELEX, Official Journal references, Regulation/ Directive numbers), case names, and cited provisions (Article/section) - then normalises, deduplicates and resolves short references (ibid., id., supra, op. cit., the above-cited judgment) to their antecedent. The front-end to verification: find every citation first, then check it. Mechanical (patterns + rules, no LLM at extraction). Jurisdiction-neutral, EU-aware. Pairs with output-scoring-en and eu-sparql-search. Use when: "list every citation in this text", "what authorities are cited", "extract the provisions", "pull the case references", "what is cited here" - before verification or before sending.

The file declares its own license as Apache-2.0. That is the author’s claim about this one file, and it is not the same thing as the license GitHub reports for the repository, which is listed with the other numbers below.

SKILL.md

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Citation extraction - find every citation before you check it

Philosophy

You can only verify what you first find. Grounding a citation checks whether it exists in the source - but it runs on a list that someone has to assemble first. This skill is that front-end: it walks the text and lists every authority, so none slips past verification. A missed citation is an unverified one.

Extraction is mechanical (patterns + rules, not an LLM) on purpose - a model asked to find citations might miss one or invent one. Local, jurisdiction-neutral, EU-aware.

Three steps (after eyecite)

Extraction - recognise and capture every reference by the patterns below.
Aggregation - resolve short references (ibid. / id. / supra / op. cit. / "the above-cited judgment") to their full antecedent, so they count as one citation, not several.
Hand-off - pass the structured list to verification (grounding) and, for EU sources, to eu-sparql-search for retrieval.

Citation patterns

Case law

ECLI (EU): ECLI:EU:C:2020:559 (Court of Justice), ECLI:EU:T:2019:... (General Court).
ECLI (national): ECLI:NL:HR:2021:..., ECLI:DE:BGH:..., ECLI:PL:SN:....
Case names / numbers: Party v Party; CJEU case numbers C-123/20, C-123/20 P (appeal), joined cases C-123/20 and C-124/20; General Court T-456/19.

EU legislation

CELEX: 32016R0679, 32019L0790 (sector + year + type + number).
Named acts: Regulation (EU) 2016/679, Directive 2019/790, Regulation (EC) No 1/2003.
Official Journal: OJ L 119, OJ C 326.

Provisions

Article 5(1)(a) GDPR, Art. 263 TFEU, section 12, § 3(2).

Aggregation - short references (antecedents)

Resolve to the full citation given earlier: ibid., id., supra, op. cit., the cited judgment, the above-cited, loc. cit.. Each points to the nearest matching antecedent in the text - count it as the same citation, but keep where it occurs.

Output format

CITATIONS FOUND (n):
| # | Type | Citation (normalised) | Occurrences (offset/page) | Antecedent (if short ref) |
| 1 | EU case law | C-311/18 (Schrems II) | p.3, p.7 (ibid.) | - |
| 2 | EU legislation | Regulation (EU) 2016/679 | p.2 | - |
| 3 | provision | Article 5(1)(a) GDPR | p.4 | - |

TO VERIFY: pass the "Citation" column to grounding; EU sources to eu-sparql-search.

Limits

Extraction catches references in a known format. A descriptive reference with no identifier ("the Court's data-protection case law") has nothing to match - mark it "no identifier, manual check".
This is not existence verification - it says what is cited, not whether the citation is real.
Patterns cover the common EU/ECLI formats; an unusual citation style may slip - at high stakes, review by hand as well.

Attribution

The extraction -> aggregation -> annotation architecture is based on eyecite (Free Law Project), BSD-2-Clause. US reporter regexes dropped; ECLI, CELEX/OJ and EU-citation patterns and the antecedent rules are MateMatic's own. MateMatic interpretation, not the position of any bar or regulator.