> For the complete documentation index, see [llms.txt](https://inthenextversion.gitbook.io/gravity-finance/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://inthenextversion.gitbook.io/gravity-finance/audits-security/security-references.md).

# Security References

### UniswapV2Pair.sol

Require checks in the Pair Contract's swap function (line 190)

```
require(!Factory.paused(), "Swap contract is paused, users can only remove liquidity");
require(amount0Out > 0 || amount1Out > 0, 'Gravity Finance: INSUFFICIENT_OUTPUT_AMOUNT');
require(amount0Out < _reserve0 && amount1Out < _reserve1, 'Gravity Finance: INSUFFICIENT_LIQUIDITY');

require(to != _token0 && to != _token1, 'Gravity Finance: INVALID_TO');
require(amount0In > 0 || amount1In > 0, 'Gravity Finance: INSUFFICIENT_INPUT_AMOUNT');
require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(10000**2), 'Gravity Finance: K');
```