The Federal Communications Commission (FCC) publishes documents from rulemakings on its [Electronic Comment Filing System][1] (ECFS). These documents include filings from 3rd parties as well as FCC-produced documents such as Public Notices, Orders, and Notices of Proposed Rulemaking (NPRM). The FCC-produced documents also eventually become published (and edited) in the Federal Register. I'm trying to find a way to link these documents.

For example, [this NPRM][2] was published on ECFS on Dec. 28, 2012, while [its equivalent][3] was published in the Federal Register on Jan. 22, 2013. The metadata for the Federal Register document is easily found through its JSON API:

        "type": "Proposed Rule",
        "toc_doc": "Rates for Interstate Inmate Calling Services",
        "full_text_xml_url": "",
        "regulations_dot_gov_info": null,
        "effective_on": null,
        "abstract_html_url": "",
        "mods_url": "",
        "html_url": "",
        "abstract": "In this document, the Federal Communications Commission (Commission) seeks comment on the inmate calling services industry and how to ensure just and reasonable rates for inmate calling services.",
        "subtype": null,
        "start_page": 4369,
        "end_page": 4376,
        "title": "Rates for Interstate Inmate Calling Services",
        "signing_date": null,
        "raw_text_url": "",
        "publication_date": "2013-01-22",
        "page_length": 8,
        "json_url": "",
        "agencies": [
                "parent_id": null,
                "url": "",
                "raw_name": "FEDERAL COMMUNICATIONS COMMISSION",
                "json_url": "",
                "name": "Federal Communications Commission",
                "id": 161
        "volume": 78,
        "topics": [],
        "regulation_id_numbers": [],
        "executive_order_number": null,
        "corrections": [],
        "citation": "78 FR 4369",
        "body_html_url": "",
        "regulation_id_number_info": {},
        "dates": "Comments are due on or before March 25, 2013. Reply comments are due on or before April 22, 2013.",
        "toc_subject": null,
        "significant": false,
        "regulations_dot_gov_url": null,
        "cfr_references": [
                "title": 47,
                "part": 64
        "pdf_url": "",
        "correction_of": null,
        "comments_close_on": "2013-04-22",
        "executive_order_notes": null,
        "docket_ids": [
            "WC Docket No. 12-375",
            "FCC 12-167"
        "action": "Notice of proposed rulemaking.",
        "public_inspection_pdf_url": "",
        "document_number": "2013-01154"

Though the FCC provides no API for ECFS, I've created a small Ruby [gem][4] which provides programmatic access to the ECFS documents. So I can query for the ECFS NPRM like so:

    filings = ECFS::Filing.query.tap do |q|
      q.docket_number = "12-375"
      q.lawfirm = "FCC"
    {"name_of_filer"=>"Wireline Competition Bureau",
     "type_of_filing"=>"NOTICE OF PROPOSED RULEMAKING",
      ["", #document linked in beginning of this stackexchange post

Is there any good practice for querying for the Federal Register equivalent of an ECFS document given an FCC docket number, date published, and type of filing (e.g. Notice of Proposed Rulemaking)?