So I'm following this article and they use the following algorithm to find the min-cut.
Algorithm:
Run Ford-Fulkerson algorithm and consider the final residual graph.
Find the set of vertices that are reachable from the source in the residual graph.
All edges which are from a reachable vertex to non-reachable vertex are minimum cut edges. Print all such edges.
Is there a proof showing this finds the min-cut?