[
  [
    "USD@usd-ledger.",
    "EUR@eur-ledger."
  ], [
    "EUR@eur-ledger.",
    "USD@usd-ledger."
  ], [
    "CAD@cad-ledger.",
    "EUR@eur-ledger."
  ], [
    "USD@usd-ledger.",
    "CAD@cad-ledger."
  ], [
    "CAD@cad-ledger.",
    "USD@usd-ledger."
  ], [
    "EUR@eur-ledger.",
    "CAD@cad-ledger."
  ], [
    "USD@usd-ledger.",
    "CNY@cny-ledger."
  ], [
    "CNY@cny-ledger.",
    "USD@usd-ledger."
  ]
]