Reversible ISSNs

issn.js

const fs = require('fs').promises
const path = require('path')

async function main () {
  const file = await fs.readFile(path.join(__dirname, 'Downloads/issns.csv'), 'utf8')
  const issns = new Set(file.trim().split('\n').slice(1))
  const printed = new Set()
  for (const issn of issns) {
    if (printed.has(issn)) continue
    const [a, b] = issn.split('-')
    if (a === b) continue
    const reversed = `${b}-${a}`
    if (issns.has(reversed)) {
      printed.add(reversed)
      console.log(`${issn}\t${reversed}\thttps://portal.issn.org/resource/ISSN/${issn}#\thttps://portal.issn.org/resource/ISSN/${reversed}#`)
    }
  }
}

main().catch(console.error)

issn.rq

SELECT DISTINCT ?issn WHERE { [] wdt:P236 ?issn }

issn.tsv