Working with multiple databases with Unit of work, Repository, EF, DI

I have two legacy databases, I have spent lots of time to find any implementation of working EF and Repository and Unit of work and DI (like structure map) that work with two (or multiple) databases. But except some advice, I have not found any implementation so far. Could anyone help me with providing any implementation or practical sample in this area that work with multiple databases? Thank you in advance.