Email Router Working - Need MS Article to share with client

Hi,

Email router reads the new emails only from the inbox of the configured mailbox and does not look into any other folder like clutter or junk. Customer wants a detailed description on this . Also the MS article that clearly states Email router will only crawls inside the inbox folder. 

If any one has this article or some some blogs written by MS person may help us. 

I have already shared the below link with the client. 

https://community.dynamics.com/crm/b/dynamicscrmsupportblog/archive/2012/11/09/email-router-demystified-explanation

Any help on this would be highly appreciated...

Thanks and Regards,

Dilip