What is unit of work and relationship with CQRS/Event Sourcing?

See
http://martinfowler.com/eaaCatalog/unitOfWork.html

But I think this pattern is not applicable for CQRS/Event Sourcing, because SAGA is the way to deal with transaction in CQRS/Event Sourcing.
Reference:
https://msdn.microsoft.com/en-us/library/jj591569.aspx