# External

- [IERC1271](/dragonswap/resources/developer-resources/smart-contracts/dragonswapv2/periphery/interfaces/external/ierc1271.md)
- [IERC20PermitAllowed](/dragonswap/resources/developer-resources/smart-contracts/dragonswapv2/periphery/interfaces/external/ierc20permitallowed.md)
- [IWSEI](/dragonswap/resources/developer-resources/smart-contracts/dragonswapv2/periphery/interfaces/external/iwsei.md)