URL Citation Search

Use this skill for

• A user gives a URL and asks which papers cited it.
• The target is a blog post, documentation page, project page, demo, GitHub page, or other web content rather than a standard paper.
• The user wants confirmed citations, not just likely matches from search results.

Workflow

1. Resolve the target page.

• Fetch the page and record the visible title.
• Extract the canonical URL if present.
• Keep obvious variants: http/https, www/non-www, trailing slash, moved domains, and mirrored or cross-posted URLs.
• Keep direct-URL variants separate from mirror URLs. The final report should distinguish direct citation from mirror citation.
• Record author and date only when they help disambiguate the page.

2. Build search keys.

• Exact full URL.
• Host plus path without protocol.
• Stable slug or final path segment.
• Exact page title.
• Title variants exposed by the page metadata or mirror pages.

3. Search in this order.

• Exact full URL and protocol-less URL in a general web search.
• Exact title and slug in a general web search.
• Site-restricted searches on academic sources such as arxiv.org, openreview.net, aclanthology.org, proceedings.neurips.cc, proceedings.mlr.press, dl.acm.org, ieeexplore.ieee.org, nature.com, link.springer.com, and ceur-ws.org.
• Mirror or cross-post URLs too. Papers often cite the mirror instead of the current canonical URL.
• If direct URL or title search is sparse, build a topical candidate pool and batch-scan likely papers. This is especially useful on arXiv when full-text search misses exact quoted strings.

4. Verify every candidate.

• Keep a work only if its PDF, HTML reference list, or in-text bibliography contains the target URL, title, slug, or a verified mirror URL.
• Search snippets alone are not enough.
• PDF-only evidence is acceptable when the exact URL appears in extracted text or PDF link annotations.
• Publisher article pages may expose references in HTML metadata such as citation_reference or dedicated bibliography pages. Use those before scraping PDFs.
• arXiv HTML bibliography entries may hide the real target inside External Links even when the visible text omits the URL. Inspect the underlying href, not just the rendered text.
• Bibliography pages, project pages, and search indexes are candidate finders, not final proof, unless they expose the actual reference entry for the citing work.

5. Deduplicate and normalize.

• If the same work exists as both a preprint and a published paper, prefer the published version in the main list and keep the preprint as an access fallback.
• Keep genuine preprints when no formal version exists.
• Do not assume the published version preserves a web citation seen in the preprint. Verify each version separately.
• Keep official same-site variants separate from mirrors. Examples: /engineering/... versus /research/..., renamed official paths, or root-versus-/home pages on the same site.
• Separate confirmed from candidate when verification is incomplete.

Output

Choose the lightest format that matches the user's ask.

• Brief list: title, year, type, and landing link.
• Citation report: title, link, DOI or arXiv ID, evidence note, and whether it is published or a preprint.
• When useful, distinguish direct, official variant, and mirror citation.
• Bib mode: return BibTeX for the citing papers. Return BibTeX for the target URL only if the user explicitly asks for it.

Heuristics That Matter

• Standard citation indexes often miss web pages, so reverse search on URL, title, and slug is usually more reliable than cited by counts.
• arXiv full-text search misses some quoted strings. If it returns nothing, switch back to general search and inspect candidate PDFs or HTML directly.
• On arXiv, broad topic searches plus batch inspection of candidate HTML reference lists can recover citations that exact-string full-text search misses.
• Moved domains and cross-posts are common. Check canonical tags and obvious mirrors before concluding that nothing cites the page.
• Official variants are common too. A paper may cite a renamed or migrated first-party URL rather than the exact URL from the seed paper.
• PDF text extraction is lossy. If the visible citation text is missing, inspect PDF link annotations or raw extracted strings for the URL.
• Publisher HTML can be better than PDF for verification because references may already be normalized into page metadata.
• Reject false positives aggressively: a paper on the same topic is not a citation unless the reference is visible.