---
license: apache-2.0
library_name: pytorch
base_model: answerdotai/ModernBERT-base
pipeline_tag: token-classification
tags:
  - bibr
  - scientific-references
  - sequence-labeling
  - crf
---

# bibr-parser-v1

ModernBERT-base + CRF reference parser for the
[bibr](https://github.com/scienceverse/bibr) scientific-paper extraction
pipeline. Takes a single segmented reference string and emits BIO field
labels over 19 field types (TITLE, AUTHOR, YEAR, CONTAINER, VOLUME,
ISSUE, PAGES, DOI, URL, ARXIV, PMID, PUBLISHER, EDITOR, EDITION,
SERIES, ACCESS_DATE, NOTE, PAGE_RANGE_START, PAGE_RANGE_END).

- **Architecture:** `answerdotai/ModernBERT-base` encoder + linear head +
  `torchcrf.CRF` decode with BIO transition constraints.
- **Tag set:** 39 BIO tags (see `bibr/ner/tags.py`).
- **Training corpus:** gold-anchored, judge-corrected references from
  psych250 + Directorate-General Economics + MDPI Social Sciences
  (~440 papers, 2026-05-09/10).

## Held-out validation (2026-05-10)

- DOI: 43% → 94% vs the prior silver-trained checkpoint.
- Year / title / authors: ≥95%.

## psych250 eval (50 papers, 2026-05-11, vs gold)

- `ref_matching_f1`: 0.969 (LLM baseline: 1.000 — partially circular,
  gold derived from LLM with judge corrections).
- `ref_title_acc`: 0.995.
- `ref_year_acc`: 0.997.
- `ref_count_ratio`: 0.988.
- `ref_doi_recall` (raw): 0.004 — URL-encoded DOI corner case in the
  gold corpus; Crossref enrichment recovers 75.7%.

## Loading

```python
from bibr.ner.parser import RefParser
parser = RefParser("thesanogoeffect/bibr-parser-v1")
fields = parser.parse(one_reference_string)
```

The `RefParser` resolver downloads the checkpoint via
`huggingface_hub.hf_hub_download` (filename: `parser_v3_gold.pt`).

## Caveats

- In-distribution: APA-style social-science references.
- Out-of-distribution: arXiv `[N] Author... CoRR, abs/...` patterns — container
  coverage drops to ~65% (vs 94% LLM). Fix path: expand gold corpus.
- URL-encoded DOIs (`info%3Adoi%2F10...`) are not in the training
  distribution; rely on downstream Crossref enrichment for those.