Good starting points for Command/Query Responsibility Segregation
Documentation:
Code, useful repositories:
CQRS Flow / overview:
Communication is done using a bus. See MessageBus for more info.
How and where is validation done?
Check Value Object concept mentioned here.
See more at the Validation page.
Saga, or a Process Manager, is used as a traffic light for processes spanning multiple aggregate boundaries. They are also useful as encapsulation of business workflows.
Some useful articles: