Reference

[1] Chain-key Bitcoin, https://wiki.internetcomputer.org/wiki/Chain-key_Bitcoin.

[2] Chain Fusion, https://internetcomputer.org/docs/current/developer-docs/multi-chain/overview.

[3] ICRC-2, https://github.com/dfinity/ICRC-1/blob/main/standards/ICRC-2/README.md.

[4] ICRC-1, https://github.com/dfinity/ICRC-1/blob/main/standards/ICRC-1/README.md.

[5] HTTPS Outcalls, https://internetcomputer.org/https-outcalls.