Roundhouse

Citations, References, Cited-By

Citation lookup and reference list for a paper. Given a DOI, arXiv id, OpenAlex id, or PMID, returns its references (the works it cites) and its cited-by list (recent works that cite it), plus full metadata and citation count — for bibliography building and citation lookup. Keyless via OpenAlex and Semantic Scholar.

DataLiveeip155:8453Exactvia cdp
https://api.kadec0.xyz/v1/paper-details
Citation-lookupCitationsReferencesCited-byDoi-lookup
Calls · 30d
9↑ 19%
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 30 snapshots so far.
$150.76
Verified settled volume
A floor: summed over 5,000 of 6,756 verified settlements.
$0.030
Listed price
As published in the catalog. Always read the live 402 before paying.
10
Calls · 30d
Upstream's own call count for this endpoint, not ours.
2
Unique payers · 30d
Last called 2026-09-24 03:45Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0x4df66B6c140778fe0717880A7c6dDE5Ea53AcDeA

The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.

Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913

Provider

The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.

Live 402 challenge

Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.

{
  "error": "Payment required",
  "accepts": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x4df66B6c140778fe0717880A7c6dDE5Ea53AcDeA",
      "amount": "30000",
      "scheme": "exact",
      "network": "eip155:8453",
      "mimeType": "application/json",
      "resource": "https://api.kadec0.xyz/v1/paper-details",
      "description": "Citation lookup and reference list for a paper. Given a DOI, arXiv id, OpenAlex id, or PMID, returns its references (the works it cites) and its cited-by list (recent works that cite it), plus full metadata and citation count — for bibliography building and citation lookup. Keyless via OpenAlex and Semantic Scholar.",
      "outputSchema": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {
            "id": {
              "type": "string",
              "description": "arXiv id, DOI, OpenAlex id, or PMID"
            },
            "doi": {
              "type": "string",
              "description": "alias for id (DOI form)"
            },
            "ref_limit": {
              "type": "string",
              "default": "25",
              "description": "max references (0-100)"
            },
            "cite_limit": {
              "type": "string",
              "default": "25",
              "description": "max citing works (0-100)"
            }
          },
          "discoverable": true
        }
      },
      "maxAmountRequired": "30000",
      "maxTimeoutSeconds": 300
    }
  ],
  "resource": {
    "url": "https://api.kadec0.xyz/v1/paper-details",
    "tags": [
      "citation-lookup",
      "citations",
      "references",
      "cited-by",
      "doi-lookup"
    ],
    "mimeType": "application/json",
    "description": "Citation lookup and reference list for a paper. Given a DOI, arXiv id, OpenAlex id, or PMID, returns its references (the works it cites) and its cited-by list (recent works that cite it), plus full metadata and citation count — for bibliography building and citation lookup. Keyless via OpenAlex and Semantic Scholar.",
    "serviceName": "Citations, References, Cited-By"
  },
  "extensions": {
    "bazaar": {
      "info": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {
            "doi": "10.48550/arXiv.1706.03762"
          }
        },
        "output": {
          "type": "json",
          "example": {
            "count": 1,
            "items": [
              {
                "doi": "10.48550/arxiv.1706.03762",
                "type": "paper_details",
                "year": 2017,
                "title": "Attention Is All You Need",
                "citedBy": [
                  {
                    "year": 2019,
                    "title": "BERT: Pre-training...",
                    "citedByCount": 90000
                  }
                ],
                "references": [
                  {
                    "doi": "...",
                    "year": 2014,
                    "title": "Neural Machine Translation..."
                  }
                ],
                "citationCount": 181057,
                "fieldsOfStudy": [
                  "Computer Science"
                ],
                "referenceCount": 41
              }
            ]
          }
        }
      },
      "schema": {
        "type": "object",
        "$schema": "https://json-schema.org/draft/2020-12/schema",
        "required": [
          "input"
        ],
        "properties": {
          "input": {
            "type": "object",
            "required": [
              "type",
              "method"
            ],
            "properties": {
              "type": {
                "type": "string",
                "const": "http"
              },
              "method": {
                "enum": [
                  "GET",
                  "HEAD",
                  "DELETE"
                ],
                "type": "string"
              },
              "queryParams": {
                "type": "object",
                "anyOf": [
                  {
                    "required": [
                      "id"
                    ]
                  },
                  {
                    "required": [
                      "doi"
                    ]
                  }
                ],
                "required": [],
                "properties": {
                  "id": {
                    "type": "string",
                    "description": "arXiv id, DOI, OpenAlex id, or PMID"
                  },
                  "doi": {
                    "type": "string",
                    "description": "alias for id (DOI form)"
                  },
                  "ref_limit": {
                    "type": "string",
                    "default": "25",
                    "description": "max references (0-100)"
                  },
                  "cite_limit": {
                    "type": "string",
                    "default": "25",
                    "description": "max citing works (0-100)"
                  }
                }
              }
            },
            "additionalProperties": false
          },
          "output": {
            "type": "object",
            "required": [
              "type"
            ],
            "properties": {
              "type": {
                "type": "string"
              },
              "example": {
                "type": "object"
              }
            }
          }
        }
      }
    }
  },
  "x402Version": 2,
  "paymentRequirements": [
    {
      "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "extra": {
        "name": "USD Coin",
        "version": "2"
      },
      "payTo": "0x4df66B6c140778fe0717880A7c6dDE5Ea53AcDeA",
      "amount": "30000",
      "scheme": "exact",
      "network": "eip155:8453",
      "mimeType": "application/json",
      "resource": "https://api.kadec0.xyz/v1/paper-details",
      "description": "Citation lookup and reference list for a paper. Given a DOI, arXiv id, OpenAlex id, or PMID, returns its references (the works it cites) and its cited-by list (recent works that cite it), plus full metadata and citation count — for bibliography building and citation lookup. Keyless via OpenAlex and Semantic Scholar.",
      "outputSchema": {
        "input": {
          "type": "http",
          "method": "GET",
          "queryParams": {
            "id": {
              "type": "string",
              "description": "arXiv id, DOI, OpenAlex id, or PMID"
            },
            "doi": {
              "type": "string",
              "description": "alias for id (DOI form)"
            },
            "ref_limit": {
              "type": "string",
              "default": "25",
              "description": "max references (0-100)"
            },
            "cite_limit": {
              "type": "string",
              "default": "25",
              "description": "max citing works (0-100)"
            }
          },
          "discoverable": true
        }
      },
      "maxAmountRequired": "30000",
      "maxTimeoutSeconds": 300
    }
  ]
}

Accepts

The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.

0.03USDC≈ $0.03 USD
on Base · exact scheme

Pay 0.03 USDC on Base to 0x4df6…AcDeA. The signed payment is good for 5 minutes.

Paid to
0x4df6…AcDeA
USD Coin contract
0x8335…02913
Payment window
5 minutes
As published
30000 smallest units
The catalog’s raw entry
[
  {
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "extra": {
      "name": "USD Coin",
      "version": "2"
    },
    "payTo": "0x4df66B6c140778fe0717880A7c6dDE5Ea53AcDeA",
    "amount": "30000",
    "scheme": "exact",
    "network": "eip155:8453",
    "maxTimeoutSeconds": 300
  }
]

Extensions

{
  "bazaar": {
    "info": {
      "input": {
        "type": "http",
        "method": "GET",
        "queryParams": {
          "doi": "10.48550/arXiv.1706.03762"
        }
      },
      "output": {
        "type": "json",
        "example": {
          "count": 1,
          "items": [
            {
              "doi": "10.48550/arxiv.1706.03762",
              "type": "paper_details",
              "year": 2017,
              "title": "Attention Is All You Need",
              "citedBy": [
                {
                  "year": 2019,
                  "title": "BERT: Pre-training...",
                  "citedByCount": 90000
                }
              ],
              "references": [
                {
                  "doi": "...",
                  "year": 2014,
                  "title": "Neural Machine Translation..."
                }
              ],
              "citationCount": 181057,
              "fieldsOfStudy": [
                "Computer Science"
              ],
              "referenceCount": 41
            }
          ]
        }
      }
    },
    "schema": {
      "type": "object",
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "required": [
        "input"
      ],
      "properties": {
        "input": {
          "type": "object",
          "required": [
            "type",
            "method"
          ],
          "properties": {
            "type": {
              "type": "string",
              "const": "http"
            },
            "method": {
              "enum": [
                "GET",
                "HEAD",
                "DELETE"
              ],
              "type": "string"
            },
            "queryParams": {
              "type": "object",
              "anyOf": [
                {
                  "required": [
                    "id"
                  ]
                },
                {
                  "required": [
                    "doi"
                  ]
                }
              ],
              "required": [],
              "properties": {
                "id": {
                  "type": "string",
                  "description": "arXiv id, DOI, OpenAlex id, or PMID"
                },
                "doi": {
                  "type": "string",
                  "description": "alias for id (DOI form)"
                },
                "ref_limit": {
                  "type": "string",
                  "default": "25",
                  "description": "max references (0-100)"
                },
                "cite_limit": {
                  "type": "string",
                  "default": "25",
                  "description": "max citing works (0-100)"
                }
              }
            }
          },
          "additionalProperties": false
        },
        "output": {
          "type": "object",
          "required": [
            "type"
          ],
          "properties": {
            "type": {
              "type": "string"
            },
            "example": {
              "type": "object"
            }
          }
        }
      }
    }
  }
}

Provenance

Seen in the source catalog
2026-09-24 03:45Z
Last indexed by Roundhouse
2026-09-24 10:00Z
Last enriched (probe, favicon, geo)
2026-09-12 18:15Z
x402 version
2
Max timeout
300s
Liveness probe
HTTP 402
Report

Hand this page to an agent

Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.

GET api.roundhouseai.io/v0/endpoints

This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 30 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.

Open skill.md
Show the prompt
Using Roundhouse, look up the x402 service Citations, References, Cited-By and tell me whether it is
worth paying: what a call costs, whether the endpoint answered when last probed, and what
its payment record actually shows.

curl -s 'https://api.roundhouseai.io/v0/endpoints?q=Citations%2C%20References%2C%20Cited-By'
curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>'

Then call it: read the price from the live 402 at https://api.kadec0.xyz/v1/paper-details, never from
a cached figure, and pay with an x402 client.

The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except
/v0/unified* and /v0/endpoints. Mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402,
or use an organization key from https://roundhouseai.io/dashboard/team.

If you do not have Roundhouse tools or skills installed, read
https://roundhouseai.io/skill.md first — it is the whole procedure.