# Existence and Uniqueness Theorems in ODEs beyond Picard and Peano?

Picard's Uniqueness Theorem requires Lipschitz continuity on $$f$$ for uniqueness. But, I have also seen examples where $$f$$ is not Lipschitz, and yet the solution is unique. Similarly with Peano's Existence Theorem.

So, I have $$2$$ questions -

1. Are there more general existence and uniqueness theorems for ODEs?
2. If not, are there theorem which guarantee uniqueness even when $$f$$ is not Lipschitz, or existence even when $$f$$ is not continuous?

If the answers to any of the above are yes, could someone also recommend some resources from where I can learn about them?