# external

- [IERC1271](/bonsaiswap-docs/developers/technical-reference/periphery/interfaces/external/ierc1271.md)
- [IERC20PermitAllowed](/bonsaiswap-docs/developers/technical-reference/periphery/interfaces/external/ierc20permitallowed.md)
- [IWETH9](/bonsaiswap-docs/developers/technical-reference/periphery/interfaces/external/iweth9.md)