Etherscan is a great place to find the source of the smart contract. To find the address I have to the stateofthedapp website and the bottom of the website has a link to the etherscan. And in the contract tab, I was able to find the smart contract code there. For an example here is the address to smartcontract for compound defi: 0x4ddc2d193948926d02f9b1fe9e1daa0718270ed5